The present invention relates generally to organic chemistry, biochemistry, pharmacology and medicine. More particularly, it relates to novel pyrrole substituted 2-indolinone compounds, and their physiologically acceptable salts and prodrugs, which modulate the activity of protein kinases (xe2x80x9cPKsxe2x80x9d) and thus are expected to exhibit a salutary effect against disorders related to abnormal PK activity.
The following is offered as background information only and is not admitted to be prior art to the present invention.
PKs are enzymes that catalyze the phosphorylation of hydroxy groups on tyrosine, serine and threonine residues of proteins. The consequences of this seemingly simple activity are staggering; cell growth, differentiation and proliferation, i.e., virtually all aspects of cell life in one way or another depend on PK activity. Furthermore, abnormal PK activity has been related to a host of disorders, ranging from relatively non-life threatening diseases such as psoriasis to extremely virulent diseases such as glioblastoma (brain cancer).
The PKs can be conveniently be broken down into two classes, the protein tyrosine kinases (PTKs) and the serine-threonine kinases (STKs).
One of the prime aspects of PTK activity is their involvement with growth factor receptors. Growth factor receptors are cell-surface proteins. When bound by a growth factor ligand, growth factor receptors are converted to an active form which interacts with proteins on the inner surface of a cell membrane. This leads to phosphorylation on tyrosine residues of the receptor and other proteins and to the formation inside the cell of complexes with a variety of cytoplasmic signaling molecules that, in turn, effect numerous cellular responses such as cell division (proliferation), cell differentiation, cell growth, expression of metabolic effects to the extracellular microenvironment, etc. For a more complete discussion, see Schlessinger and Ullrich, Neuron, 9:303-391 (1992) which is incorporated by reference, including any drawings, as if fully set forth herein.
Growth factor receptors with PTK activity are known as receptor tyrosine kinases (xe2x80x9cRTKsxe2x80x9d). They comprise a large family of transmembrane receptors with diverse biological activity. At present, at least nineteen (19) distinct subfamilies of RTKs have been identified. An example of these is the subfamily designated the xe2x80x9cHERxe2x80x9d RTKs, which include EGFR (epithelial growth factor receptor), HER2, HER3 and HER4. These RTKs consist of an extracellular glycosylated ligand binding domain, a transmembrane domain and an intracellular cytoplasmic catalytic domain that can phosphorylate tyrosine residues on proteins.
Another RTK subfamily consists of insulin receptor (IR), insulin-like growth factor I receptor (IGF-1R) and insulin receptor related receptor (IRR). IR and IGF-1R interact with insulin, IGF-I and IGF-II to form a heterotetramer of two entirely extracellular glycosylated a subunits and two xcex2 subunits which cross the cell membrane and which contain the tyrosine kinase domain.
A third RTK subfamily is referred to as the platelet derived growth factor receptor (xe2x80x9cPDGFRxe2x80x9d) group, which includes PDGFRxcex1, PDGFRxcex2, CSFIR, c-kit and c-fms. These receptors consist of glycosylated extracellular domains composed of variable numbers of immunoglobin-like loops and an intracellular domain wherein the tyrosine kinase domain is interrupted by unrelated amino acid sequences.
Another group which, because of its similarity to the PDGFR subfamily, is sometimes subsumed into the later group is the fetus liver kinase (xe2x80x9cflkxe2x80x9d) receptor subfamily. This group is believed to be made of up of kinase insert domain-receptor fetal liver kinase-1 (KDR/FLK-1), flk-1R, flk-4 and fms-like tyrosine kinase 1 (flt-1).
A further member of the tyrosine kinase growth factor receptor family is the fibroblast growth factor (xe2x80x9cFGFxe2x80x9d) receptor subgroup. This group consists of four receptors, FGFR1-4, and seven ligands, FGF1-7. While not yet well defined, it appears that the receptors consist of a glycosylated extracellular domain containing a variable number of immunoglobin-like loops and an intracellular domain in which the tyrosine kinase sequence is interrupted by regions of unrelated amino acid sequences.
Still another member of the tyrosine kinase growth factor receptor family is the vascular endothelial growth factor (VEGFxe2x80x3) receptor subgroup. VEGF is a dimeric glycoprotein similar to PDGF but has different biological functions and target cell specificity in vivo. In particular, VEGF is presently thought to play an essential role is vasculogenesis and angiogenesis.
A more complete listing of the known RTK subfamilies is described in Plowman et al., DNandP, 7(6):334-339 (1994) which is incorporated by reference, including any drawings, as if fully set forth herein.
In addition to the RTKs, there also exists a family of entirely intracellular PTKs called xe2x80x9cnon-receptor tyrosine kinasesxe2x80x9d or xe2x80x9ccellular tyrosine kinases.xe2x80x9d This latter designation, abbreviated xe2x80x9cCTK,xe2x80x9d will be used herein. CTKs do not contain extracellular and transmembrane domains. At present, over 24 CTKs in 11 subfamilies (Src, Frk, Btk, Csk, Abl, Zap70, Fes, Fps, Fak, Jak and Ack) have been identified. The Src subfamily appear so far to be the largest group of CTKs and includes Src, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk. For a more detailed discussion of CTKs, see Bolen, Oncogene, 8:2025-2031 (1993), which is incorporated by reference, including any drawings, as if fully set forth herein.
The serine/threonine kinases, STKs, like the CTKs, are predominantly intracellular although there are a few receptor kinases of the STK type. STKs are the most common of the cytosolic kinases; i.e., kinases that perform their function in that part of the cytoplasm other than the cytoplasmic organelles and cytoskelton. The cytosol is the region within the cell where much of the cell""s intermediary metabolic and biosynthetic activity occurs; e.g., it is in the cytosol that proteins are synthesized on ribosomes.
RTKs, CTKs and STKs have all been implicated in a host of pathogenic conditions including, significantly, cancer. Other pathogenic conditions which have been associated with PTKs include, without limitation, psoriasis, hepatic cirrhosis, diabetes, angiogenesis, restenosis, ocular diseases, rheumatoid arthritis and other inflammatory disorders, immunological disorders such as autoimmune disease, cardiovascular disease such as atherosclerosis and a variety of renal disorders.
With regard to cancer, two of the major hypotheses advanced to explain the excessive cellular proliferation that drives tumor development relate to functions known to be PK regulated. That is, it has been suggested that malignant cell growth results from a breakdown in the mechanisms that control cell division and/or differentiation. It has been shown that the protein products of a number of proto-oncogenes are involved in the signal transduction pathways that regulate cell growth and differentiation. These protein products of proto-oncogenes include the extracellular growth factors, transmembrane growth factor PTK receptors (RTKs), cytoplasmic PTKs (CTKs) and cytosolic STKs, discussed above.
In view of the apparent link between PK-related cellular activities and wide variety of human disorders, it is no surprise that a great deal of effort is being expended in an attempt to identify ways to modulate PK activity. Some of these have involved biomimetic approaches using large molecules patterned on those involved in the actual cellular processes (e.g., mutant ligands (U.S. Pat. No. 4,966,849); soluble receptors and antibodies (App. No. WO 94/10202, Kendall and Thomas, Proc. Nat""l Acad. Sci., 90:10705-09 (1994), Kim, et al., Nature, 362:841-844 (1993)); RNA ligands (Jelinek, et al., Biochemistry, 33:10450-56); Takano, et al., Mol. Bio. Cell 4:358A (1993); Kinsella, et al., Exp. Cell Res. 199:56-62 (1992); Wright, et al., J. Cellular Phys., 152:448-57) and tyrosine kinase inhibitors (WO 94/03427; WO 92/21660; WO 91/15495; WO 94/14808; U.S. Pat. No. 5,330,992; Mariani, et al., Proc. Am. Assoc. Cancer Res., 35:2268 (1994)).
In addition to the above, attempts have been made to identify small molecules which act as PK inhibitors. For example, bis-monocylic, bicyclic and heterocyclic aryl compounds (PCT WO 92/20642), vinylene-azaindole derivatives (PCT WO 94/14808) and 1-cyclopropyl-4-pyridylquinolones (U.S. Pat. No. 5,330,992) have been described as tyrosine kinase inhibitors. Styryl compounds (U.S. Pat. No. 5,217,999), styryl-substituted pyridyl compounds (U.S. Pat. No. 5,302,606), quinazoline derivatives (EP App. No. 0 566 266 A1), selenaindoles and selenides (PCT WO 94/03427), tricyclic polyhydroxylic compounds (PCT WO 92/21660) and benzylphosphonic acid compounds (PCT WO 91/15495) have all been described as PTK inhibitors useful in the treatment of cancer.
Our own efforts to identify small organic molecules which modulate PK activity and which, therefore, are expected to be useful in the treatment and prevention of disorders involving abnormal PK activity, has led us to the discovery of a family of novel pyrrole substituted 2-indolinone compounds which exhibit PK modulating ability and are thereby expected to have a salutary effect against disorders related to abnormal PK activity; it is these compounds which is the subject of this invention.
Thus, the present invention relates generally to novel pyrrole substituted 2-indolinones which modulate the activity of receptor tyrosine kinases (RTKs), non-receptor protein tyrosine kinases (CTKs) and serine/threonine protein kinases (STKs). In addition, the present invention relates to the preparation and use of pharmaceutical compositions of the disclosed compounds and their physiologically acceptable salts and prodrugs in the treatment or prevention of PK driven disorders such as, by way of example and not limitation, cancer, diabetes, hepatic cirrhosis, cardiovasacular disease such ase atherosclerosis, angiogenesis, immunological disease such as autoimmune disease and renal disease.
The terms xe2x80x9c2-indolinone,xe2x80x9d indolin-2-one and xe2x80x9c2-oxindolexe2x80x9d are used interchangeably herein to refer to a molecule having the chemical structure: 
A xe2x80x9cpyrrolexe2x80x9d refers to a molecule having the chemical structure: 
xe2x80x9cPyrrole substituted 2-indolinonexe2x80x9d and xe2x80x9c3-pyrrolidenyl-2-indolinonexe2x80x9d are used interchangeably herein to refer to a chemical compound having the general structure shown in Formula 1.
A xe2x80x9cpharmaceutical compositionxe2x80x9d refers to a mixture of one or more of the compounds described herein, or physiologically acceptable salts or prodrugs thereof, with other chemical components, such as physiologically acceptable carriers and excipients. The purpose of a pharmaceutical composition is to facilitate administration of a compound to an organism.
A xe2x80x9cprodrugxe2x80x9d refers to an agent which is converted into the parent drug in vivo. Prodrugs are often useful because, in some situations, they may be easier to administer than the parent drug. They may, for instance, be bioavailable by oral administration whereas the parent drug is not. The prodrug may also have improved solubility in pharmaceutical compositions over the parent drug. An example, without limitation, of a prodrug would be a compound of the present invention which is administered as an ester (the xe2x80x9cprodrugxe2x80x9d) to facilitate transmittal across a cell membrane where water solubility is detrimental to mobility but then is metabolically hydrolyzed to the carboxylic acid, the active entity, once inside the cell where water solubility is beneficial.
A further example of a prodrug might be a short polypeptide, for example, without limitation, a 2-10 amino acid polypeptide, bonded through a terminal amino group to a carboxy group of a compound of this invention wherein the polypeptide is hydrolyzed or metabolized in vivo to release the active molecule.
A xe2x80x9cpyrrole aldehydexe2x80x9d refers to a molecule having the chemical structure: 
As used herein, a xe2x80x9cphysiologically acceptable carrierxe2x80x9d refers to a carrier or diluent that does not cause significant irritation to an organism and does not abrogate the biological activity and properties of the administered compound.
An xe2x80x9cexcipientxe2x80x9d refers to an inert substance added to a pharmaceutical composition to further facilitate administration of a compound. Examples, without limitation, of excipients include calcium carbonate, calcium phosphate, various sugars and types of starch, cellulose derivatives, gelatin, vegetable oils and polyethylene glycols.
1. CHEMISTRY
A. General Structural Features
In one aspect, the the present invention relate to pyrrole substituted 2-indolinones which, in addition to being otherwise optionally substituted on both the pyrrole and 2-indolinone portions of the compound, are necessarily substituted on the pyrrole moiety with one or more hydrocarbon chains which themselves are substituted with at least one polar group. Physiologically acceptable salts and prodrugs of the claimed compounds are also within the scope of this invention.
A xe2x80x9chydrocarbon chainxe2x80x9d refers to an alkyl, alkenyl or alkynyl group, as defined herein.
A xe2x80x9cpolarxe2x80x9d group refers to a group wherein the nuclei of the atoms covalently bound to each other to form the group do not share the electrons of the covalent bond(s) joining them equally; that is the electron cloud is denser about one atom than another. This results in one end of the covalent bond(s) being relatively negative and the other end relatively positive; i.e., there is a negative pole and a positive pole. Examples of polar groups include, without limitation, hydroxy, alkoxy, carboxy, nitro, cyano, amino, ammonium, amido, ureido, sulfonamido, sulfinyl, sulfonyl, phosphono, morpholino, piperazinyl and tetrazolo.
While not being bound to any particular theory, applicants at this time believe that the polar groups may interact electronically, for example, but without limitation, through hydrogen bonds, Van der Walls forces and/or ionic bonds (but not covalent bonding), with the amino acids at a PTK active site. These interactions may assist the molecules of this invention to bind to an active site with sufficient tenacity to interfere with or prevent the natural substrate from entering the site. Polar groups may also contribute to the selectivity of the compounds; i.e., one polar group may have greater affinity for a PTK binding domain than other polar groups so that the compound containing the first particular polar group is more potent than the compounds containing the other polar groups.
Thus, one aspect of the present invention relates to compounds having the following chemical structure: 
R1 is selected from the group consisting of hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, aryl, hydroxy, alkoxy, C-carboxy, O-carboxy, acetyl, C-amido, C-thioamido, sulfonyl and trihalomethanesulfonyl.
R2 is selected from the group consisting of hydrogen, halo, alkyl, cycloalkyl, aryl, heteroaryl and heteroalicyclic.
R3, R4, R5 and R6 are independently selected from the group consisting of hydrogen, alkyl, trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, sulfinyl, sulfonyl, S-sulfonamido, N-sulfonamido, trihalomethane-sulfonamido, carbonyl, C-carboxy, O-carboxy, C-amido, N-amido, cyano, nitro, halo, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, amino and xe2x80x94NR11R12.
R11 and R12 are independently selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, carbonyl, acetyl, sulfonyl, trifluoromethanesulfonyl and, combined, a five- or six-member heteroalicyclic ring.
R3 and R4, R4 and R5, or R4 and R5 may combine to form a six-member aryl ring, a methylenedioxy group or an ethylenedioxy group.
R7 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, carbonyl, acetyl, C-amido, C-thioamido, amidino, C-carboxy, O-carboxy, sulfonyl and trihalomethane-sulfonyl.
R8, R9 and R10 are independently selected from the group consisting of hydrogen, alkyl, trihaloalkyl, cycloalkyl, alkenyl, alkynyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, sulfinyl, sulfonyl, S-sulfonamido, N-sulfonamido, carbonyl, C-carboxy, O-carboxy, cyano, nitro, halo, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, amino and xe2x80x94NR11R12, providing, however that at least one of R8, R9 or R10 is a group having the formula xe2x80x94(alk1)Z.
Alk1 is selected from the group consisting of alkyl, alkenyl or alkynyl.
Z is a polar group.
As used herein, the term xe2x80x9calkylxe2x80x9d refers to a saturated aliphatic hydrocarbon including straight chain and branched chain groups. Preferably, the alkyl group has 1 to 20 carbon atoms (whenever a numerical range; e.g. xe2x80x9c1-20xe2x80x9d, is stated herein, it means that the group, in this case the alkyl group, may contain 1 carbon atom, 2 carbon atoms, 3 carbon atoms, etc. up to and including 20 carbon atoms). More preferably, it is a medium size alkyl having 1 to 10 carbon atoms. Most preferably, it is a lower alkyl having 1 to 4 carbon atoms. The alkyl group may be substituted or unsubstituted. When substituted, the substituent group(s) is preferably one or more individually selected from cycloalkyl, aryl, heteroaryl, heteroalicyclic, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, halo, carbonyl, thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, C-carboxy, O-carboxy, nitro, silyl, amino and xe2x80x94NR11R12, with R11 and R12 as defined above.
A xe2x80x9ccycloalkylxe2x80x9d group refers to an all-carbon monocyclic or fused ring (i.e., rings which share an adjacent pair of carbon atoms) group wherein one of more of the rings does not have a completely conjugated pi-electron system. Examples, without limitation, of cycloalkyl groups are cyclopropane, cyclobutane, cyclopentane, cyclopentene, cyclohexane, adamantane, cyclohexadiene, cycloheptane and, cycloheptatriene. A cycloalkyl group may be substituted or unsubstituted. When substituted, the substituent group(s) is preferably one or more individually selected from alkyl, aryl, heteroaryl, heteroalycyclic, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, halo, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, C-amido, N-amido, nitro, amino and xe2x80x94NR11R12, with R11 and R12 as defined above.
An xe2x80x9calkenylxe2x80x9d group refers to an alkyl group, as defined herein, consisting of at least two carbon atoms and at least one carbon-carbon double bond.
An xe2x80x9calkynylxe2x80x9d group refers to an alkyl group, as defined herein, consisting of at least two carbon atoms and at least one carbon-carbon triple bond.
An xe2x80x9carylxe2x80x9d group refers to an all-carbon monocyclic or fused-ring polycyclic (i.e., rings which share adjacent pairs of carbon atoms) groups having a completely conjugated pi-electron system. Examples, without limitation, of aryl groups are phenyl, naphthalenyl and anthracenyl. The aryl group may be substituted or unsubstituted. When substituted, the substituted group(s) is preferably one or more selected from halo, trihalomethyl, alkyl, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, nitro, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, sulfinyl, sulfonyl, amino and xe2x80x94NR11R12, with R11 and R12 as defined herein.
As used herein, a xe2x80x9cheteroarylxe2x80x9d group refers to a monocyclic or fused ring (i.e., rings which share an adjacent pair of atoms) group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur and, in addition, having a completely conjugated pi-electron system. Examples, without limitation, of heteroaryl groups are pyrrole, furan, thiophene, imidazole, oxazole, thiazole, pyrazole, pyridine, pyrimidine, quinoline, isoquinoline, purine and carbazole. The heteroaryl group may be substituted or unsubstituted. When substituted, the substituted group(s) is preferably one or more selected from alkyl, cycloalkyl, halo, trihalomethyl, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, nitro, carbonyl, thiocarbonyl, sulfonamido, C-carboxy, O-carboxy, sulfinyl, sulfonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, C-amido, N-amido, amino and xe2x80x94NR11R12 with R11 and R12 as defined above.
A xe2x80x9cheteroalicyclicxe2x80x9d group refers to a monocyclic or fused ring group having in the ring(s) one or more atoms selected from the group consisting of nitrogen, oxygen and sulfur. The rings may also have one or more double bonds. However, the rings do not have a completely conjugated pi-electron system. The heteroalicyclic ring may be substituted or unsubstituted. When substituted, the substituted group(s) is preferably one or more selected from alkyl, cycloaklyl, halo, trihalomethyl, hydroxy, alkoxy, aryloxy, mercapto, alkylthio, arylthio, cyano, nitro, carbonyl, thiocarbonyl, C-carboxy, O-carboxy, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl, sulfinyl, sulfonyl, C-amido, N-amido, amino and xe2x80x94NR11R12 with R11 and R12 as defined above.
A xe2x80x9chydroxyxe2x80x9d group refers to an xe2x80x94OH group.
An xe2x80x9calkoxyxe2x80x9d group refers to both an xe2x80x94O-alkyl and an xe2x80x94O-cycloalkyl group, as defined herein.
An xe2x80x9caryloxyxe2x80x9d group refers to both an xe2x80x94O-aryl and an xe2x80x94O-heteroaryl group, as defined herein.
A xe2x80x9cmercaptoxe2x80x9d group refers to an xe2x80x94SH group.
A xe2x80x9calkylthioxe2x80x9d group refers to both an S-alkyl and an xe2x80x94S-cycloalkyl group, as defined herein.
A xe2x80x9carylthioxe2x80x9d group refers to both an xe2x80x94S-aryl and an xe2x80x94S-heteroaryl group, as defined herein.
A xe2x80x9ccarbonylxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)xe2x80x94Rxe2x80x3 group, where Rxe2x80x3 is selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, heteroaryl (bonded through a ring carbon) and heteroalicyclic (bonded through a ring carbon), as defined herein.
An xe2x80x9caldehydexe2x80x9d group refers to a carbonyl group where Rxe2x80x3 is hydrogen.
A xe2x80x9cthiocarbonylxe2x80x9d group refers to a xe2x80x94C(xe2x95x90S)xe2x80x94Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
A xe2x80x9cC-carboxyxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)Oxe2x80x94Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
An xe2x80x9cO-carboxyxe2x80x9d group refers to a xe2x80x94OC(xe2x95x90O)Rxe2x80x3 group, with Rxe2x80x3 as defined herein.
An xe2x80x9cesterxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)Oxe2x80x94Rxe2x80x3 group with Rxe2x80x3 as defined herein except that Rxe2x80x3 cannot be hydrogen.
An xe2x80x9cacetylxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)CH3 group.
A xe2x80x9ccarboxylic acidxe2x80x9d group refers to a C-carboxy group in which Rxe2x80x3 is hydrogen.
A xe2x80x9chaloxe2x80x9d group refers to fluorine, chlorine, bromine or iodine.
A xe2x80x9ctrihalomethylxe2x80x9d group refers to a xe2x80x94CX3 group wherein X is a halo group as defined herein.
A xe2x80x9ctrihalomethanesulfonylxe2x80x9d group refers to a X3CS(xe2x95x90O)2xe2x80x94 groups with X as defined above.
A xe2x80x9ccyanoxe2x80x9d group refers to a xe2x80x94Cxe2x89xa1N group.
A xe2x80x9csulfinylxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)xe2x80x94Rxe2x80x3 group wherein, in addition to being as defined above, Rxe2x80x3 may also be a hydroxy group.
A xe2x80x9csulfonylxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)2Rxe2x80x3 group wherein, in addition to being as defined above, Rxe2x80x3 may also be a hydroxy group.
A xe2x80x9cmethylenedioxyxe2x80x9d group refers to a xe2x80x94OCH2Oxe2x80x94 group where the two oxygen atoms are bonded to adjacent carbon atoms.
An xe2x80x9cethylenedioxyxe2x80x9d group refers to a xe2x80x94OCH2CH2Oxe2x80x94 where the two oxygen atoms are bonded to adjacent carbon atoms.
An xe2x80x9cS-sulfonamidoxe2x80x9d group refers to a xe2x80x94S(xe2x95x90O)2NR11R12 group, with R11 and R12 as defined herein.
An xe2x80x9cN-sulfonamidoxe2x80x9d group refers to a xe2x80x94NR11S(xe2x95x90O)2R12 group, with R11 and R12 as defined herein.
An xe2x80x9cO-carbamylxe2x80x9d group refers to a xe2x80x94OC(xe2x95x90O)NR11R12 group with R11 and R12 as defined herein.
An xe2x80x9cN-carbamylxe2x80x9d group refers to a R12OC(xe2x95x90O)NR11xe2x80x94 group, with R11 and R12 as defined herein.
An xe2x80x9cO-thiocarbamylxe2x80x9d group refers to a xe2x80x94OC(xe2x95x90S)NR11R12 group with R11 and R12 as defined herein.
An xe2x80x9cN-thiocarbamylxe2x80x9d group refers to a R12OC(xe2x95x90S)NR11xe2x80x94 group, with R11 and R12 as defined herein.
An xe2x80x9caminoxe2x80x9d group refers to an xe2x80x94NR11R12 group, wherein R11 and R12 are both hydrogen.
A xe2x80x9cC-amidoxe2x80x9d group refers to a xe2x80x94C(xe2x95x90O)NR11R12 group with R11 and R12 as defined herein.
An xe2x80x9cN-amidoxe2x80x9d group refers to a R12C(xe2x95x90O)NR11xe2x80x94 group, with R11 and R12 as defined herein.
A xe2x80x9cammoniumxe2x80x9d group refers to a xe2x80x94+NHR11R12 group wherein R11 and R12 are independently selected from the group consisting of alkyl, cycloalkyl, aryl, and heteroaryl.
A xe2x80x9cureidoxe2x80x9d group refers to a xe2x80x94NR11C(xe2x95x90O)NR12R13 group, with R11 and R12 as defined herein and R13 defined the same as R11 and R12.
A xe2x80x9cguanidinoxe2x80x9d group refers to a xe2x80x94R11NC(xe2x95x90N)NR12R13 group, with R11, R12 and R13 as defined herein.
A xe2x80x9camidinoxe2x80x9d group refers to a R11R12NC(xe2x95x90N)xe2x80x94 group, with R11 and R12 as defined herein.
A xe2x80x9cnitroxe2x80x9d group refers to a xe2x80x94NO2 group.
A xe2x80x9cphosphonylxe2x80x9d group refers to a xe2x80x94OP(xe2x95x90O)2ORxe2x80x3, with Rxe2x80x3 as defined herein.
A xe2x80x9cmorpholinoxe2x80x9d group refers to a group having the chemical structure: 
A xe2x80x9cpiperazinylxe2x80x9d group refers to a group having the chemical structure: 
A xe2x80x9ctetrazoloxe2x80x9d group refers to a group having the chemical structure: 
B. Preferred Structural Features
It is a presently preferred feature of this invention that R1 is hydrogen.
It is also a presently preferred feature of this invention that R2 is hydrogen.
It is likewise a presently preferred feature of this invention that R7 is hydrogen.
It is a presently preferred feature of this invention that all three of the above limitations exist in the same molecule; i.e., that, in a compound of this invention, R1, R2 and R7 are hydrogen.
It is also presently preferred that R3, R4, R5 and R6 are selected from the group consisting of hydrogen, unsubstituted lower alkyl, lower alkyl substituted with a group selected from the group consisting of hydroxy, halo, C-carboxy substituted with a group selected from the group consisting of hydrogen and unsubstituted lower alkyl, amino or xe2x80x94NR11R12; unsubstituted lower alkyl alkoxy, lower alkoxy substituted with one or more halo groups, lower alkoxy substituted with a group consisting of unsubstituted aryl or aryl substituted with one or more groups independently selected from the group consisting of unsubstituted lower alkyl, hydroxy, unsubstituted lower alkyl alkoxy, halo, amino, unsubstituted lower alkyl S-sulfonamido or xe2x80x94NR11R12, unsubstituted aryl or aryl substituted with one or more groups independently selected from the group consisting of unsubstituted lower alkyl, unsubstituted lower alkyl alkoxy, lower alkoxy substituted with one or more halo groups, lower alkoxy substituted with a group selected from the group consisting of unsubstituted aryl or aryl substituted with one or more groups independently selected from the group consisting of unsubstituted lower alkyl, hydroxy, unsubstituted lower alkyl alkoxy, halo, amino, unsubstituted lower alkyl S-sulfonamido or xe2x80x94NR11R12, hydroxy, amino, unsubstituted lower alkyl sulfonamido, C-carboxy substituted with a groups selected from the group consisting of hydrogen or unsubstituted lower alkyl, morpholino, xe2x80x94NR11R12, trihalomethyl, aryl, aryl substituted with one or more groups independently selected from the group consisting of hydroxy, halo, trihalomethyl, amino, xe2x80x94NR11R12, sulfonamido, C-carboxy substituted with a group selected from the group consisting of hydrogen or unsubstituted lower alkyl, unsubstituted lower alkyl or lower alkyl substituted with a group selected from the group consisting of hydroxy, halo, C-carboxy substituted with a group selected from the group consisting of hydrogen or unsubstituted lower alkyl, amino or xe2x80x94NR11R12, unsubstituted heteroalicyclic, heteroalicyclic substituted with one or more groups independently selected from the group consisting of halo, hydroxy, unsubstituted lower alkyl, unsubstituted lower alkyl carbonyl, hydroxy, unsubstituted lower alkyl alkoxy or alkoxy substituted with one or more halo groups, unsubstituted aryloxy, aryloxy substituted with one or more groups independently selected from the group consisting of unsubstituted lower alkyl, trihalomethyl, halo, hydroxy, amino or xe2x80x94NR11R12, mercapto, unsubstituted lower alkyl alkylthio, unsubstituted arylthio, arylthio substituted with one or more groups selected from the group consisting of halo, hydroxy, amino or xe2x80x94NR11R12, C-carboxy substituted with a group selected from the group consisting of hydrogen and unsubstituted lower alkyl, unsubstituted lower alkyl O-carboxy, unsubstituted lower alkyl S-sulfonamido, nitro, unsubstituted lowe alkyl C-amido, unsubstituted lower alkyl N-amido, amino and xe2x80x94R11R12.
In another presently preferred embodiments of this invention, R3, R4, R5 and R6 are independently selected from the group consisting of hydrogen, halo, unsubstituted lower alkyl, lower alkyl substituted with one or more groups selected from the group consisting of hydroxy, halo, C-carboxy substituted with a group selected from the group consisting of hydrogen or unsubstituted lower alkyl, amino or xe2x80x94NR11R12, unsubstituted lower alkyl alkoxy, lower alkyl alkoxy substituted with one or more halo groups, unsubstituted aryloxy, aryloxy substituted with one or more groups indepedently selected from the group consisting of unsubstituted lower alkyl, lower alkyl substituted with one or more halo groups, hydroxy, unsubstituted lower alkyl alkoxy, halo, amino or xe2x80x94NR11R12, S-sulfonamido wherein R11 and R12 are independently selected from the group consisting of hydrogen and unsubstituted lower alkyl, unsubstituted aryl, aryl substituted with one or more groups independently selected from the group consisting of halo, unsubstituted lower alkyl, lower alkyl substituted with one or more halo groups, unsubstituted lower alkyl alkoxy, amino or xe2x80x94NR11R12, unsubstituted heteroaryl, heteroaryl substituted with one or more groups independently selected from the group consisting of unsubstituted lower alkyl, lower alkyl substituted with one or more halo groups, unsubstituted lower alkyl alkoxy, hydroxy, halo, amino or xe2x80x94NR11R12, unsubstituted heteroalicyclic, heteroalicyclic substituted with one or more groups independently selected from the group consisting of halo, hydroxy, unsubstituted lower alkyl, lower alkyl substituted with one or more halo groups, unsubstituted lower alkyl alkoxy, amino or xe2x80x94NR11R12, unsubstituted lower alkyl O-carboxy, C-amido wherein R11 and R12 are independently selected from the group consisting of hydrogen, unsubstituted lower alkyl and unsubstituted aryl, and, N-amido wherein R11 and R12 are independently selected from the group consisting of hydrogen, unsubstituted lower alkyl and unsubstituted aryl.
It is a presently preferred feature of this invention that one of R8, R9 and R10 is xe2x80x94(alk1)Z while the other two are independently selected from the group consisting of hydrogen, hydroxy, unsubstituted lower alkyl, unsubstituted lower alkenyl, unsubstituted lower alkynyl, unsubstituted lower alkyl alkoxy, lower alkoxy substituted with one or more halo groups, unsubstituted aryl alkoxy, amino, xe2x80x94NR11R12, halo, C-carboxy substituted with a groups selected from the group consisting of hydrogen or unsubstituted lower alkyl, unsubstituted lower alkyl O-carboxy, unsubstituted lower alkyl C-amido, unsubstituted lower alkyl N-amido, acetyl, unsubstituted lower alkyl S-sulfonamido, unsubstituted aryl or aryl substituted with a group selected from the group consisting of halo, hydroxy, unsubstituted lower alkyl alkoxy, alkoxy substituted with one or more halo groups, C-carboxy substituted with a groups selected from the group consisting of hydrogen or unsubstituted lower alkyl, unsubstituted lower alkyl O-carboxy, amino, unsubstituted lower alkyl S-sulfonamido and xe2x80x94NR11R12.
It is a presently preferred feature of this invention that R8 and R10 are selected from the groups consisting of hydrogen and unsubstituted lower alkyl.
It is also a presently preferred feature of this invention that alk1 is an unsubstituted lower alkyl group.
In yet another presently preferred feature of this invention, Z is selected from the group consisting of hydroxy, amino, xe2x80x94NR11R12, quarternary ammonium, C-carboxy substituted with a group selected from the group consisting of hydrogen or unsubstituted lower alkyl, C-amido substituted with groups selected from the group consisting of hydrogen and unsubstituted lower alkyl, morpholino, piperadinyl, tetrazolo and phosphonyl.
A further presently preferred feature of this invention is that alk1 is a two to four carbon unsubstituted lower alkyl group and Z is a carboxylic acid.
It is a presently preferred feature of this invention that R9 is alk1Z.
It is likewise a presently preferred feature of this invention that R11 and R12 are independently selected from the group comprising hydrogen, unsubstituted lower alkyl, hydroxy, unsubstituted lower alkyl alkoxy, unsubstituted lower alkyl carbonyl, unsubstituted lower alkyl O-carboxy and acetyl.
In another presently preferred embodiment of this invention R1, R2, R3, R4, R5, R6 and R7 are hydrogen, R8 and R10 are methyl and R9 is xe2x80x94CH2CH2C(xe2x95x90O)OH.
It is also a presently preferred embodiment of this invention that R1, R2, R3, R4, R5, R6, R7 and R8 are hydrogen, R10 is methyl and R9 is xe2x80x94CH2CH2C(xe2x95x90O)OH.
In yet another presently preferred embodiment of this invention R7 is selected from the group consisting of: hydrogen, unsubstituted lower alkyl, and lower alkyl substituted with a group selected from the group consisting of unsubstituted cycloalkyl, unsubstituted aryl, and, aryl substituted with a group selected from hydroxy, unsubstituted lower alkyl alkoxy and halo.
It is also a presently preferred embodiment of this invention that z is selected from the group consisting of xe2x80x94C(xe2x95x90O)NR13R14 wherein R13 and R14 are independently selected from the group consisting of hydrogen, unsubstituted lower alkyl, lower alkyl substituted with a group selected from the group consisting of amino and xe2x80x94NR11R12, unsubstituted aryl, aryl substituted with one or more groups selected from the group consisting of halo, hydroxy, unsubstituted lower alkyl alkoxy and trihalomethyl, unsubstituted heteroaryl, unsubstituted heteroalicyclic, and, combined, a five-member or a six-member unsubstituted heteroalicyclic, and, xe2x80x94NR11R12, wherein, R11 and R12 are independently selected from the group consisting of unsubstituted lower alkyl and, combined, a five-member or a six-member unsubstituted heteroalicyclic ring.
Yet another presently preferred embodiment of this invention is that R7 is selected from the group consisting of unsubstituted lower alkyl, lower alkyl substituted with one or more groups selected from the group consisting of unsubstituted cycloalkyl, unsubstituted aryl, aryl substituted with one or more groups independently selected from the group consisting of halo and unsubstituted lower alkyl alkoxy and unsubstituted lower alkyl carboxyalkyl, and Z is selected from the group consisting of unsubstituted C-carboxy and unsubstituted lower alkyl C-carboxy.
Finally, it is a presently preferred embodiment of this invention that R3 R4, R5, and R6 are independently selected from the group consisting of hydrogen, halo, unsubstituted lower alkyl, lower alkyl substituted with one or more hydroxy groups, unsubstituted lower alkoxy, unsubstituted aryl, aryl substituted with one or more unsubstituted lower alkoxy groups, and xe2x80x94S(O)2NR11R12,R5 is hydrogen, R6 is xe2x80x94NR11R12, and R11 and R12 are independently selected from the group consisting of hydrogen, unsubstituted lower alkyl and, combined, a five-member or a six-member unsubstituted heteroalicyclic ring.
The chemical formulae referred to herein may exhibit the phenomena of tautomerism and structural isomerism. For example, the compounds described herein may adopt an E or a Z configuration about the double bond connecting the 2-indolinone moiety to the pyrrole moiety or they may be a mixture of E and Z. This invention encompasses any tautomeric or structural isomeric form and mixtures thereof which possess the ability to modulate RTK, CTK and/or STK activity and is not limited to any one tautomeric or structural isomeric form.
2. SYNTHESIS/COMBINATORIAL LIBRARIES
An additional aspect of this invention is a combinatorial library of at least ten 3-pyrrolidinyl-2-indolinone compounds that can be formed by reacting oxindoles of structure 2 with aldehydes of structure 3. 
wherein R1-R10 have the meanings set forth above.
As used herein, a xe2x80x9ccombinatorial libraryxe2x80x9d refers to all the compounds formed by the reaction of each compound of one dimension with a compound in each of the other dimensions in a multi-dimensional array of compounds. In the context of the present invention, the array is two dimensional and one dimension represents all the oxindoles of the invention and the second dimension represents all the aldehydes of the invention. Each oxindole may be reacted with each and every aldehyde in order to form a 3-pyrrolidinyl-2-indolinone compound. All 3-pyrrolidinyl-2-indolinone compounds formed in this way are within the scope of the present invention. Also within the scope of the present invention are smaller combinatorial libraries formed by the reaction of some of the oxindoles with all of the aldehydes, all of the oxindoles with some of the aldehydes, or some of the oxindoles with some of the aldehydes.
The oxindole in the above combinatorial library is preferably selected from the group consisting of oxindole itself and substituted oxindoles such as, without limitation, 6-bromooxindole, 5-hydroxyoxindole, 5-methoxyoxindole, 6-methoxyoxindole, 5-phenylaminosulfonyloxindole, 4-[2-(2-isopropylphenoxy)-ethyl]oxindole, 4-[2-(3-isopropylphenoxy)ethyl]oxindole, 4-[2-(4-isopropylphenoxy)ethyl]oxindole, 5-fluorooxindole, 6-fluorooxindole, 7-fluorooxindole, 6-trifluoromethyloxindole, 5-chlorooxindole, 6-chlorooxindole, indole-4-carboxylic acid, 5-bromooxindole, 6-(N-acetamido)-oxindole, 4-methyloxindole, 5-methyloxindole, 4-methyl-5-chlorooxindole, 5-ethyloxindole, 6-hydroxyoxindole, 5-acetyloxindole, oxindole-5-carboxylic acid, 5-methoxyoxindole, 6-methoxyoxindole, 5-aminooxindole, 6-aminooxindole, 4-(2-N-morpholinoethyl)oxindole, 7-azaoxindole, oxindole-4-carabamic acid t-butyl ester, oxindole-6-carbamic acid t-butyl ester, 4-(2-carboxyethyl)oxindole, 4-n-butyloxindole, 4,5-dimethoxyoxindole, 6-(methanesulfonamido)oxindole, 6-(benzamido)oxindole, 5-ethoxyoxindole, 6-phenyloxindole, 6-(2-methoxyphen-1-yl)oxindole, 6-(3-methoxyphen-1-yl)oxindole, 6-(4-methoxyphen-1-yl)oxindole, 5-aminosulfonyloxindole, 5-isopropylaminosulfonyloxindole, dimethylaminosulfonyloxindole, 5-(N-morpholinosulfonyl)oxindole and 4-(2-hydroxyethyl)oxindole.
The aldehyde in the above combinatorial library is preferably selected from the group consisting of, without limitation, 3-(5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-4-methyl-1H-pyrrol-3-yl) propionic acid, 3-(1-benzyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-1-methoxycarbonylmethyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl) propionic acid, 3-[5-formyl-1-(3-methoxy-benzyl)-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-(1-cyclohexylmethyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid methyl ester, 3-[1-(2,2-dimethyl-propyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 1,3,5-trimethyl-4-(3-morpholin-4-yl-3-oxo-propyl)-1H-pyrrole-2-carbaldehyde, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(2-morpholin-4-yl-ethyl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-phenylpropionamide, 1,3,5-trimethyl-4-(3-oxo-3-piperidin-1-yl-propyl)-1H-pyrrole-2-carbaldehyde, 1,3,5-trimethyl-4-(3-oxo-3-pyrrolidin-1-yl-propyl)-1H-pyrrole-2-carbaldehyde, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-methoxy-phenyl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-methoxyphenyl)propionamide, N-(4-fluoro-phenyl)-3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-trifluoromethylphenyl)propionamide, 3-[5-formyl-1-(3-methoxy-benzyl)-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3-(1-cyclohexylmethyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-[1-(3-fluoro-benzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-(1-benzyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-[1-(4-fluorobenzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-[1-(4-fluorobenzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3-[1-(3-fluoro-benzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3,5-dimethyl-4-(3-morpholin-4-yl-propyl)-1H-pyrrole-2-carbaldehyde, 4-(3-dimethylamino-propyl)-3,5-dimethyl-1H-pyrrole-2-carbaldehyde, 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid, 3,5-dimethyl-4-(4-methyl-piperazine-1-carbonyl)-1H-pyrrole-2-carbaldehyde, 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (2-dimethylaminoethyl) amide.
Another aspect of this invention provides a method for the synthesis of a 3-pyrrolidinyl-2-indolinone of formula 1 comprising reacting an oxindole of formula 2 with an aldehyde of formula 3 in a solvent, preferably in the presence of a base.
Examples of the oxindoles of formula 2 which may be reacted with an aldehyde of formula 3 to give the 3-pyrrolidinyl-2-indolinones of formula 1 are oxindole itself and substituted oxindoles such as, without limitation, 6-bromooxindole, 5-hydroxyoxindole, 5-methoxyoxindole, 6-methoxyoxindole, 5-phenylaminosulfonyloxindole, 4-[2-(2-isopropylphenoxy)-ethyl]oxindole, 4-[2-(3-isopropylphenoxy)ethyl]oxindole, 4-[2-(4-isopropylphenoxy)ethyl]oxindole, 5-fluorooxindole, 6-fluorooxindole, 7-fluorooxindole, 6-trifluoromethyloxindole, 5-chlorooxindole, 6-chlorooxindole, indole-4-carboxylic acid, 5-bromooxindole, 6-(N-acetamido)-oxindole, 4-methyloxindole, 5-methyloxindole, 4-methyl-5-chlorooxindole, 5-ethyloxindole, 6-hydroxyoxindole, 5-acetyloxindole, oxindole-5-carboxylic acid, 5-methoxyoxindole, 6-methoxyoxindole, 5-aminooxindole, 6-aminooxindole, 4-(2-N-morpholinoethyl)oxindole, 7-azaoxindole, oxindole-4-carabamic acid t-butyl ester, oxindole-6-carbamic acid t-butyl ester, 4-(2-carboxyethyl)oxindole, 4-n-butyloxindole, 4,5-dimethoxyoxindole, 6-(methanesulfonamido)oxindole, 6-(benzamido)oxindole, 5-ethoxyoxindole, 6-phenyloxindole, 6-(2-methoxyphen-1-yl)oxindole, 6-(3-methoxyphen-1-yl)oxindole, 6-(4-methoxyphen-1-yl)oxindole, 5-aminosulfonyloxindole, 5-isopropylaminosulfonyloxindole, dimethylaminosulfonyloxindole, 5-(N-morpholinosulfonyl)oxindole and 4-(2-hydroxyethyl)oxindole.
Examples of aldehydes of structure 3 which may be reacted with oxindoles of structure 2 are, without limitation, 3-(5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-4-methyl-1H-pyrrol-3-yl) propionic acid, 3-(1-benzyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-1-methoxycarbonylmethyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl) propionic acid, 3-[5-formyl-1-(3-methoxy-benzyl)-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-(1-cyclohexylmethyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid methyl ester, 3-[1-(2,2-dimethyl-propyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 1,3,5-trimethyl-4-(3-morpholin-4-yl-3-oxopropyl)-1H-pyrrole-2-carbaldehyde, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(2-morpholin-4-yl-ethyl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-phenylpropionamide, 1,3,5-trimethyl-4-(3-oxo-3-piperidin-1-yl-propyl)-1H-pyrrole-2-carbaldehyde, 1,3,5-trimethyl-4-(3-oxo-3-pyrrolidin-1-yl-propyl)-1H-pyrrole-2-carbaldehyde, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-methoxy-phenyl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-methoxy-phenyl)propionamide, N-(4-fluoro-phenyl)-3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)propionamide, 3-(5-formyl-1,2,4-trimethyl-1H-pyrrol-3-yl)-N-(4-trifluoromethyl-phenyl)propionamide, 3-[5-formyl-1-(3-methoxybenzyl)-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3-(1-cyclohexylmethyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-[1-(3-fluoro-benzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-(1-benzyl-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl) propionic acid, 3-[1-(4-fluorobenzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid methyl ester, 3-[1-(4-fluoro-benzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3-[1-(3-fluoro-benzyl)-5-formyl-2,4-dimethyl-1H-pyrrol-3-yl] propionic acid, 3,5-dimethyl-4-(3-morpholin-4-yl-propyl)-1H-pyrrole-2-carbaldehyde, 4-(3-dimethylamino-propyl)-3,5-dimethyl-1H-pyrrole-2-carbaldehyde, 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid, 3,5-dimethyl-4-(4-methyl-piperazine-1-carbonyl)-1H-pyrrole-2-carbaldehyde, 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (2-dimethylaminoethyl) amide.
The reaction may be carried out in the presence of a base. The base may be an organic or an inorganic base. If an organic base is used, preferably it is a nitrogen base. Examples of organic nitrogen bases include, but are not limited to, diisopropylamine, trimethylamine, triethylamine, aniline, pyridine, 1,8-diazabicyclo[5.4.1]undec-7-ene, pyrrolidine and piperidine.
Examples of inorganic bases are, without limitation, ammonia, alkali metal or alkaline earth hydroxides, phosphates, carbonates, bicarbonates, bisulfates and amides. The alkali metals include, lithium, sodium and potassium while the alkaline earths include calcium, magnesium and barium.
In a presently preferred embodiment of this invention, when the solvent is a protic solvent, such as water or alcohol, the base is an alkali metal or an alkaline earth inorganic base, preferably, a alkali metal or an alkaline earth hydroxide.
It will be clear to those skilled in the art, based both on known general principles of organic synthesis and on the disclosures herein which base would be most appropriate for the reaction contemplated.
The solvent in which the reaction is carried out may be a protic or an aprotic solvent, preferably it is a protic solvent. A xe2x80x9cprotic solventxe2x80x9d is a solvent which has hydrogen atom(s) covalently bonded to oxygen or nitrogen atoms which renders the hydrogen atoms appreciably acidic and thus capable of being xe2x80x9csharedxe2x80x9d with a solute through hydrogen bonding. Examples of protic solvents include, without limitation, water and alcohols.
An xe2x80x9caprotic solventxe2x80x9d may be polar or non-polar but, in either case, does not contain acidic hydrogens and therefore is not capable of hydrogen bonding with solutes. Examples, without limitation, of non-polar aprotic solvents, are pentane, hexane, benzene, toluene, methylene chloride and carbon tetrachloride. Examples of polar aprotic solvents are chloroform, tetrahydrofuran, dimethylsulfoxide and dimethylformamide.
In a presently preferred embodiment of this invention, the solvent is a protic solvent, preferably water or an alcohol such as ethanol.
The reaction is carried out at temperatures greater than room temperature. The temperature is generally from about 30xc2x0 C. to about 150xc2x0 C., preferably about 80xc2x0 C. to about 100xc2x0 C., most preferable about 75xc2x0 C. to about 85xc2x0 C., which is about the boiling point of ethanol. By xe2x80x9caboutxe2x80x9d is meant that the temperature range is preferably within 10 degrees Celcius of the indicated temperature, more preferably within 5 degrees Celcius of the indicated temperature and, most preferably, within 2 degrees Celcius of the indicated temperature. Thus, for example, by xe2x80x9cabout 75xc2x0 C.xe2x80x9d is meant 75xc2x0 C.xc2x110xc2x0 C., preferably 75xc2x0 C.xc2x15xc2x0 C. and most preferably, 75xc2x0 C.xc2x12xc2x0 C.
3. BIOCHEMISTRY/PHARMACOTHERAPY
Another aspect of this invention relates to a method for the modulation of the catalytic activity of a PK by contacting a PK with a compound of this invention or a physiologically acceptable salt or prodrug thereof.
As used herein, xe2x80x9cPKxe2x80x9d refers to receptor protein tyrosine kinase (RTKs), non-receptor or xe2x80x9ccellularxe2x80x9d tyrosine kinase (CTKs) and serine-threonine kinases (STKs).
The term xe2x80x9cmethodxe2x80x9d refers to manners, means, techniques and procedures for accomplishing a given task including, but not limited to, those manners, means, techniques and procedures either known to, or readily developed from known manners, means, techniques and procedures by, practitioners of the chemical, pharmaceutical, biological, biochemical and medical arts.
As used herein, the term xe2x80x9cmodulationxe2x80x9d or xe2x80x9cmodulatingxe2x80x9d refers to the alteration of the catalytic activity of RTKs, CTKs and STKs. In particular, modulating refers to the activation of the catalytic activity of RTKs, CTKs and STKs, preferably the activation or inhibition of the catalytic activity of RTKs, CTKs and STKs, depending on the concentration of the compound or salt to which the RTK, CTK or STK is exposed or, more preferably, the inhibition of the catalytic activity of RTKs, CTKs and STKs.
The term xe2x80x9ccatalytic activityxe2x80x9d as used herein refers to the rate of phosphorylation of tyrosine under the influence, direct or indirect, of RTKs and/or CTKs or the phosphorylation of serine and threonine under the influence, direct or indirect, of STKs.
The term xe2x80x9ccontactingxe2x80x9d as used herein refers to bringing a compound of this invention and a target PK together in such a manner that the compound can affect the catalytic activity of the PK, either directly, i.e., by interacting with the kinase itself, or indirectly, i.e., by interacting with another molecule on which the catalytic activity of the kinase is dependent. Such xe2x80x9ccontactingxe2x80x9d can be accomplished xe2x80x9cin vitro,xe2x80x9d i.e., in a test tube, a petri dish or the like. In a test tube, contacting may involve only a compound and a PK of interest or it may involve whole cells. Cells may also be maintained or grown in cell culture dishes and contacted with a compound in that environment. In this context, the ability of a particular compound to affect a PK related disorder, i.e., the IC50 of the compound, defined below, can be determined before use of the compounds in vivo with more complex living organisms is attempted. For cells outside the organism, multiple methods exist, and are well-known to those skilled in the art, to get the PKs in contact with the compounds including, but not limited to, direct cell microinjection and numerous transmembrane carrier techniques.
A further aspect of this invention is that the modulation of the catalytic activity of PKs using a compound of this invention may be carried out in vitro or in vivo.
xe2x80x9cIn vitroxe2x80x9d refers to procedures performed in an artificial environment such as, e.g., without limitation, in a test tube or culture medium.
As used herein, xe2x80x9cin vivoxe2x80x9d refers to procedures performed within a living organism such as, without limitation, a mouse, rat or rabbit.
A still further aspect of this invention is that the protein kinase whose catalytic activity is being modulated by a compound of this invention is selected from the group consisting of receptor protein tyrosine kinases, cellular tyrosine kinases and serine-threonine kinases.
It is an aspect of this invention that the receptor protein kinase whose catalytic activity is modulated by a compound of this invention is selected from the group consisting of EGF, HER2, HER3, HER4, IR, IGF-1R, IRR, PDGFRxcex1, PDGFRxcex2, CSFIR, C-Kit, C-fms, Flk-1R, Flk4, KDR/Flk-1, Flt-1, FGFR-1R, FGFR-2R, FGFR-3R and FGFR-4R.
In addition, it is an aspect of this invention that the cellular tyrosine kinase whose catalytic activity is modulated by a compound of this invention is selected from the group consisting of Src, Frk, Btk, Csk, Abl, ZAP70, Fes/Fps, Fak, Jak, Ack, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk.
Another aspect of this invention is that the serine-threonine protein kinase whose catalytic activity is modulated by a compound of this invention is selected from the group consisting of CDK2 and Raf.
A pharmaceutical composition of a compound of this invention with a pharmaceutically acceptable carrier is yet another aspect of this invention. Such pharmaceutical composition may contain excipients as well.
A method for treating or preventing a protein kinase related disorder in an organism comprising administering a therapeutically effective amount of a compound, salt or prodrug that is a 3-pyrrolidenyl-2-indolinone of the present invention to the organism is another aspect of this invention.
As used herein, xe2x80x9cPK related disorder,xe2x80x9d xe2x80x9cPK driven disorder,xe2x80x9d and xe2x80x9cabnormal PK activityxe2x80x9d all refer to a condition characterized by inappropriate, i.e., under or, more commonly, over, PK catalytic activity, where the particular PK can be an RTK, a CTK or an STK. Inappropriate catalytic activity can arise as the result of either: (1) PK expression in cells which normally do not express PKs, (2) increased PK expression leading to unwanted cell proliferation, differentiation and/or growth, or, (3) decreased PK expression leading to unwanted reductions in cell proliferation, differentiation and/or growth. Over-activity of a PK refers to either amplification of the gene encoding a particular PK or production of a level of PK activity which can correlate with a cell proliferation, differentiation and/or growth disorder (that is, as the level of the PK increases, the severity of one or more of the symptoms of the cellular disorder increases). Under-activity is, of course, the converse, wherein the severity of one or more symptoms of a cellular disorder increase as the level of the PK activity decreases.
As used herein, the terms xe2x80x9cpreventxe2x80x9d, xe2x80x9cpreventingxe2x80x9d and xe2x80x9cpreventionxe2x80x9d refer to a method for barring an organism from acquiring a PK related disorder in the first place.
As used herein, the terms xe2x80x9ctreatxe2x80x9d, xe2x80x9ctreatingxe2x80x9d and xe2x80x9ctreatmentxe2x80x9d refer to a method of alleviating or abrogating a PK mediated cellular disorder and/or its attendant symptoms. With regard particularly to cancer, these terms simply mean that the life expectancy of an individual affected with a cancer will be increased or that one or more of the symptoms of the disease will be reduced.
The term xe2x80x9corganismxe2x80x9d refers to any living entity comprised of at least one cell. A living organism can be as simple as, for example, a single eukariotic cell or as complex as a mammal, including a human being.
The term xe2x80x9ctherapeutically effective amountxe2x80x9d as used herein refers to that amount of the compound being administered which will relieve to some extent one or more of the symptoms of the disorder being treated. In reference to the treatment of cancer, a therapeutically effective amount refers to that amount which has the effect of (1) reducing the size of the tumor, (2) inhibiting (that is, slowing to some extent, preferably stopping) tumor metastasis, (3) inhibiting to some extent (that is, slowing to some extent, preferably stopping) tumor growth, and/or, (4) relieving to some extent (or, preferably, eliminating) one or more symptoms associated with the cancer.
It is an aspect of this invention that the above-referenced protein kinase related disorder is selected from the group consisting of a receptor protein tyrosine kinase related disorder, a cellular tyrosine kinase disorder and a serine-threonine kinase related disorder.
In yet another aspect of this invention, the above referenced protein kinase related disorder is selected from the group consisting of an EGFR related disorder, a PDGFR related disorder, an IGFR related disorder and a flk related disorder.
The above referenced protein kinase related disorder is a cancer selected from the group consisting of squamous cell carcinoma, sarcomas such as Kaposi""s sarcoma, astrocytoma, glioblastoma, lung cancer, bladder cancer, colorectal cancer, gastrointestinal cancer, head and neck cancer, melanoma, ovarian cancer, prostate cancer, breast cancer, small-cell lung cancer and glioma in a further aspect of this invention.
The above referenced protein kinase related disorder is selected from the group consisting of diabetes, a hyperproliferation disorder, von Hippel-Lindau disease, restenosis, fibrosis, psoriasis, osteoarthritis, rheumatoid arthritis, an inflammatory disorder and angiogenesis in yet another aspect of this invention.
Additional disorders which may be treated or prevented using the compounds of this invention are immunological disorders such as autoimmune disease (AIDS) and cardiovasular disorders such as atherosclerosis.
It is as aspect of this invention that a chemical compound that modulates the catalytic activity of a protein kinase may be identified by contacting cells expressing said protein kinase with a compound, salt or prodrug that is a 3-pyrrolidenyl-2-indolinone of the present invention and then monitoring said cells for an effect.
By xe2x80x9cmonitoringxe2x80x9d is meant observing or detecting the effect of contacting a compound with a cell expressing a particular PK. The observed or detected effect can be a change in cell phenotype, in the catalytic activity of a PK or a change in the interaction of a PK with a natural binding partner. Techniques for observing or detecting such effects are well-known in the art.
The above-referenced effect is selected from a change or an absence of change in a cell phenotype, a change or absence of change in the catalytic activity of said protein kinase or a change or absence of change in the interaction of said protein kinase with a natural binding partner in a final aspect of this invention.
xe2x80x9cCell phenotypexe2x80x9d refers to the outward appearance of a cell or tissue or the biological function of the cell or tissue. Examples, without limitation, of a cell phenotype are cell size, cell growth, cell proliferation, cell differentiation, cell survival, apoptosis, and nutrient uptake and use. Such phenotypic characteristics are measurable by techniques well-known in the art.
A xe2x80x9cnatural binding partnerxe2x80x9d refers to a polypeptide that binds to a particular PK in a cell. Natural binding partners can play a role in propagating a signal in a PK-mediated signal transduction process. A change in the interaction of the natural binding partner with the PK can manifest itself as an increased or decreased concentration of the PK/natural binding partner complex and, as a result, in an observable change in the ability of the PK to mediate signal transduction.
It is also an aspect of this invention that a compound described herein, or its salt or prodrug, might be combined with other chemotherapeutic agents for the treatment of the diseases and disorders discussed above. For instance, a compound, salt or prodrug of this invention might be combined with alkylating agents such as fluorouracil (5-FU) alone or in further combination with leukovorin; or other alkylating agents such as, without limitation, other pyrimidine analogs such as UFT, capecitabine, gemcitabine and cytarabine, the alkyl sulfonates, e.g., busulfan (used in the treatment of chronic granulocytic leukemia), improsulfan and piposulfan; aziridines, e.g., benzodepa, carboquone, meturedepa and uredepa; ethyleneimines and methylmelamines, e.g., altretamine, triethylenemelamine, triethylenephosphoramide, triethylenethiophosphoramide and trimethylolmelamine; and the nitrogen mustards, e.g., chlorambucil (used in the treatment of chronic lymphocytic leukemia, primary macroglobulinemia and non-Hodgkin""s lymphoma), cyclophosphamide (used in the treatment of Hodgkin""s disease, multiple myeloma, neuroblastoma, breast cancer, ovarian cancer, lung cancer, Wilm""s tumor and rhabdomyosarcoma), estramustine, ifosfamide, novembrichin, prednimustine and uracil mustard (used in the treatment of primary thrombocytosis, non-Hodgkin""s lymphoma, Hodgkin""s disease and ovarian cancer); and triazines, e.g., dacarbazine (used in the treatment of soft tissue sarcoma).
Likewise a compound, salt or prodrug of this invention might be expected to have a beneficial effect in combination with other antimetabolite chemotherapeutic agents such as, without limitation, folic acid analogs, e.g. methotrexate (used in the treatment of acute lymphocytic leukemia, choriocarcinoma, mycosis fungiodes breast cancer, head and neck cancer and osteogenic sarcoma) and pteropterin; and the purine analogs such as mercaptopurine and thioguanine which find use in the treatment of acute granulocytic, acute lymphocytic and chronic granulocytic leukemias.
A compound, salt or prodrug of this invention might also be expected to prove efficacious in combination with natural product based chemotherapeutic agents such as, without limitation, the vinca alkaloids, e.g., vinblastin (used in the treatment of breast and testicular cancer), vincristine and vindesine; the epipodophylotoxins, e.g., etoposide and teniposide, both of which are useful in the treatment of testicular cancer and Kaposi""s sarcoma; the antibiotic chemotherapeutic agents, e.g., daunorubicin, doxorubicin, epirubicin, mitomycin (used to treat stomach, cervix, colon, breast, bladder and pancreatic cancer), dactinomycin, temozolomide, plicamycin, bleomycin (used in the treatment of skin, esophagus and genitourinary tract cancer); and the enzymatic chemotherapeutic agents such as L-asparaginase.
In addition to the above, a compound, salt or prodrug of this invention might be expected to have a beneficial effect used in combination with the platinum coordination complexes (cisplatin, etc.); substituted ureas such as hydroxyurea; methylhydrazine derivatives, e.g., procarbazine; adrenocortical suppressants, e.g., mitotane, aminoglutethimide; and hormone and hormone antagonists such as the adrenocorticosteriods (e.g., prednisone), progestins (e.g., hydroxyprogesterone caproate); estrogens (e.g., diethylstilbesterol); antiestrogens such as tamoxifen; androgens, e.g., testosterone propionate; and aromatase inhibitors (such as anastrozole.
Finally, the combination of a compound of this invention might be expected to be particularly effective in combination with mitoxantrone or paclitaxel for the treatment of solid tumor cancers or leukemias such as, without limitation, acute myelogenous (non-lymphocytic) leukemia.
A presently preferred compound of this invention which might be expected to have a beneficial effect in combination with one or more of the above chemotherapeutic agents is 3-[2,4-Dimethyl-5-(2-oxo-1,2-dihydroindol-3-ylidenemethyl)-1H-pyrrol-3-yl]propionic acid.
1. BRIEF DESCRIPTION OF THE TABLES
TABLE 1 shows the chemical structures and biological activity of some exemplary compounds of this invention. The compound numbers correspond to the Example numbers in the Examples section. That is, the synthesis of Compound 1 in Table 1 is described in Example 1. The bioassays used are described in detail below. The results are reported in terms of IC50, the micromolar (xcexcm) concentration of the compound being tested which causes a 50% change in the activity of the target PKT compared to the activity of the PTK in a control to which no test compound has been added. Specifically, the results shown indicate the concentration of a test compound needed to cause a 50% reduction of the activity of the target PTK. The compounds presented in Table 1 are exemplary only and are not to be construed as limiting the scope of this invention in any manner.
TABLE 2 shows the chemical structures of some additional compounds of this invention. As in Table 1, the compound numbers correspond to Example numbers. The general description of the bioassays above applies as well to the bioassays shown in Table 2.
2. INDICATIONS/TARGET DISEASES
The PKs whose catalytic activity is modulated by the compounds of this invention include protein tyrosine kinases of which there are two types, receptor tyrosine kinases (RTKs) and cellular tyrosine kinases (CTKs), and serine-threonine kinases (STKs). RTK mediated signal transduction, is initiated by extracellular interaction with a specific growth factor (ligand), followed by receptor dimerization, transient stimulation of the intrinsic protein tyrosine kinase activity and phosphorylation. Binding sites are thereby created for intracellular signal transduction molecules and lead to the formation of complexes with a spectrum of cytoplasmic signaling molecules that facilitate the appropriate cellular response (e.g., cell division, metabolic effects on the extracellular microenvironment, etc.). See, Schlessinger and Ullrich, 1992, Neuron 9:303-391.
It has been shown that tyrosine phosphorylation sites on growth factor receptors function as high-affinity binding sites for SH2 (src homology) domains of signaling molecules. Fantl et al., 1992, Cell 69:413-423, Songyang et al., 1994, Mol. Cell. Biol. 14:2777-2785), Songyang et al., 1993, Cell 72:767-778, and Koch et al., 1991, Science 252:668-678. Several intracellular substrate proteins that associate with RTKs have been identified. They may be divided into two principal groups: (1) substrates that have a catalytic domain, and (2) substrates which lack such domain but which serve as adapters and associate with catalytically active molecules. Songyang et al., 1993, Cell 72:767-778. The specificity of the interactions between receptors and SH2 domains of their substrates is determined by the amino acid residues immediately surrounding the phosphorylated tyrosine residue. Differences in the binding affinities between SH2 domains and the amino acid sequences surrounding the phosphotyrosine residues on particular receptors are consistent with the observed differences in their substrate phosphorylation profiles. Songyang et al., 1993, Cell 72:767-778. These observations suggest that the function of each RTK is determined not only by its pattern of expression and ligand availability but also by the array of downstream signal transduction pathways that are activated by a particular receptor. Thus, phosphorylation provides an important regulatory step which determines the selectivity of signaling pathways recruited by specific growth factor receptors, as well as differentiation factor receptors.
STKs, being primarily cytosolic, affect the internal biochemistry of the cell, often as a down-line response to a PTK event. STKs have been implicated in the signaling process which initiates DNA synthesis and subsequent mitosis leading to cell proliferation.
Thus, PK signal transduction results in, among other responses, cell proliferation, differentiation, growth and metabolism. Abnormal cell proliferation may result in a wide array of disorders and diseases, including the development of neoplasia such as carcinoma, sarcoma, glioblastoma and hemangioma, disorders such as leukemia, psoriasis, arteriosclerosis, arthritis and diabetic retinopathy and other disorders related to uncontrolled angiogenesis and/or vasculogenesis.
A precise understanding of the mechanism by which the compounds of this invention inhibit PKs is not required in order to practice the present invention. However, while not hereby being bound to any particular mechanism or theory, it is believed that the compounds interact with the amino acids in the catalytic region of PKs. PKs typically possess a bi-lobate structure wherein ATP appears to bind in the cleft between the two lobes in a region where the amino acids are conserved among PKs. Inhibitors of PKs are believed to bind by non-covalent interactions such as hydrogen bonding, van der Waals forces and ionic interactions in the same general region where the aforesaid ATP binds to the PKs. More specifically, it is thought that the 2-indolinone component of the compounds of this invention binds in the general space normally occupied by the adenine ring of ATP. Specificity of a particular molecule for a particular PK may then arise as the result of additional interactions between the various substituents on the 2-indolinone core and the amino acid domains specific to particular PKs. Thus, different indolinone substituents may contribute to preferential binding to particular PKs. The ability to select compounds active at different ATP (or other nucleotide) binding sites makes the compounds of this invention useful for targeting any protein with such a site. The compounds disclosed herein may thus have utility as in vitro assays for such proteins as well as exhibiting in vivo therapeutic effects through interaction with such proteins.
In another aspect, the protein kinase, the catalytic activity of which is modulated by contact with a compound of this invention, is a protein tyrosine kinase, more particularly, a receptor protein tyrosine kinase. Among the receptor protein tyrosine kinases whose catalytic activity can be modulated with a compound of this invention, or salt thereof, are, without limitation, EGF, HER2, HER3, HER4, IR, IGF-1R, IRR, PDGFRxcex1, PDGFRxcex2, CSFIR, C-Kit, C-fms, Flk-1R, Flk4, KDR/Flk-1, Flt-1, FGFR-1R, FGFR-2R, FGFR-3R and FGFR-4R.
The protein tyrosine kinase whose catalytic activity is modulated by contact with a compound of this invention, or a salt or a prodrug thereof, can also be a non-receptor or cellular protein tyrosine kinase (CTK). Thus, the catalytic activity of CTKs such as, without limitation, Src, Frk, Btk, Csk, Abl, ZAP70, Fes, Fps, Fak, Jak, Ack, Yes, Fyn, Lyn, Lck, Blk, Hck, Fgr and Yrk, may be modulated by contact with a compound or salt of this invention.
Still another group of PKs which may have their catalytic activity modulated by contact with a compound of this invention are the serine-threonine protein kinases such as, without limitation, CDK2 and Raf.
In another aspect, this invention relates to a method for treating or preventing a PK related disorder by administering a therapeutically effective amount of a compound of this invention, or a salt or a prodrug thereof, to an organism.
It is also an aspect of this invention that a pharmaceutical composition containing a compound of this invention or a salt or prodrug thereof is administered to an organism for the purpose of preventing or treating a PK related disorder.
This invention is therefore directed to compounds that modulate PK signal transduction by affecting the enzymatic activity of RTKs, CTKs and/or STKs, thereby interfering with the signals transduced by such proteins. More particularly, the present invention is directed to compounds which modulate RTK, CTK and/or STK mediated signal transduction pathways as a therapeutic approach to cure many kinds of solid tumors, including but not limited to carcinomas, sarcomas including Kaposi""s sarcoma, erythroblastoma, glioblastoma, meningioma, astrocytoma, melanoma and myoblastoma. Treatment or prevention of non-solid tumor cancers such as leukemia are also contemplated by this invention. Indications may include, but are not limited to brain cancers, bladder cancers, ovarian cancers, gastric cancers, pancreas cancers, colon cancers, blood cancers, lung cancers and bone cancers.
Further examples, without limitation, of the types of disorders related to inappropriate PK activity that the compounds described herein may be useful in preventing, treating and studying, are cell proliferative disorders, fibrotic disorders and metabolic disorders.
Cell proliferative disorders, which may be prevented, treated or further studied by the present invention include cancer, blood vessel proliferative disorders and mesangial cell proliferative disorders.
Blood vessel proliferative disorders refer to disorders related to abnormal vasculogenesis (blood vessel formation) and angiogenesis (spreading of blood vessels). While vasculogenesis and angiogenesis play important roles in a variety of normal physiological processes such as embryonic development, corpus luteum formation, wound healing and organ regeneration, they also play a pivotal role in cancer development where they result in the formation of new capillaries needed to keep a tumor alive. Other examples of blood vessel proliferation disorders include arthritis, where new capillary blood vessels invade the joint and destroy cartilage, and ocular diseases, like diabetic retinopathy, where new capillaries in the retina invade the vitreous, bleed and cause blindness.
Two structurally related RTKs have been identified to bind VEGF with high affinity: the fms-like tyrosine 1 (fit-1) receptor (Shibuya et al., 1990, Oncogene,5:519-524; De Vries et al., 1992, Science, 255:989-991) and the KDR/FLK-1 receptor, also known as VEGF-R2. Vascular endothelial growth factor (VEGF) has been reported to be an endothelial cell specific mitogen with in vitro endothelial cell growth promoting activity. Ferrara and Henzel, 1989, Biochein. Biophys. Res. Comm., 161:851-858; Vaisman et al., 1990, J. Biol. Chem., 265:19461-19566. Information set forth in U.S. application Ser. Nos. 08/193,829, 08/038,596 and 07/975,750, strongly suggest that VEGF is not only responsible for endothelial cell proliferation, but also is the prime regulator of normal and pathological angiogenesis. See generally, Klagsburn and Soker, 1993, Current Biology, 3(10)699-702; Houck, et al., 1992, J. Biol. Chem., 267:26031-26037.
Normal vasculogenesis and angiogenesis play important roles in a variety of physiological processes such as embryonic development, wound healing, organ regeneration and female reproductive processes such as follicle development in the corpus luteum during ovulation and placental growth after pregnancy. Folkman and Shing, 1992, J. Biological Chem., 267(16):10931-34. Uncontrolled vasculogenesis and/or angiogenesis has been associated with diseases such as diabetes as well as with malignant solid tumors that rely on vascularization for growth. Klagsburn and Soker, 1993, Current Biology, 3(10):699-702; Folkham, 1991, J. Natl. Cancer Inst., 82:4-6; Weidner, et al., 1991, New Engl. J. Med., 324:1-5.
The surmised role of VEGF in endothelial cell proliferation and migration during angiogenesis and vasculogenesis indicates an important role for the KDR/FLK-1 receptor in these processes. Diseases such as diabetes mellitus (Folkman, 198, in XIth Congress of Thrombosis and Haemostasis (Verstraeta, et al., eds.), pp. 583-596, Leuven University Press, Leuven) and arthritis, as well as malignant tumor growth may result from uncontrolled angiogenesis. See e.g., Folkman, 1971, N. Engl. J. Med., 285:1182-1186. The receptors to which VEGF specifically binds are an important and powerful therapeutic target for the regulation and modulation of vasculogenesis and/or angiogenesis and a variety of severe diseases which involve abnormal cellular growth caused by such processes. Plowman, et al., 1994, DNandP, 7(6):334-339. More particularly, the KDR/FLK-1 receptor""s highly specific role in neovascularization make it a choice target for therapeutic approaches to the treatment of cancer and other diseases which involve the uncontrolled formation of blood vessels.
Thus, one aspect of the present invention relates to compounds capable of regulating and/or modulating tyrosine kinase signal transduction including KDR/FLK-1 receptor signal transduction in order to inhibit or promote angiogenesis and/or vasculogenesis, that is, compounds that inhibit, prevent, or interfere with the signal transduced by KDR/FLK-1 when activated by ligands such as VEGF. Although it is believed that the compounds of the present invention act on a receptor or other component along the tyrosine kinase signal transduction pathway, they may also act directly on the tumor cells that result from uncontrolled angiogenesis.
Although the nomenclature of the human and murine counterparts of the generic xe2x80x9cflk-Ixe2x80x9d receptor differ, they are, in many respects, interchangeable. The murine receptor, Flk-1, and its human counterpart, KDR, share a sequence homology of 93.4% within the intracellular domain. Likewise, murine FLK-I binds human VEGF with the same affinity as mouse VEGF, and accordingly, is activated by the ligand derived from either species. Millauer et al., 1993, Cell, 72:835-846; Quinn et al., 1993, Proc. Natl. Acad. Sci. USA, 90:7533-7537. FLK-1 also associates with and subsequently tyrosine phosphorylates human RTK substrates (e.g., PLC-xcex3 or p85) when co-expressed in 293 cells (human embryonal kidney fibroblasts).
Models which rely upon the FLK-1 receptor therefore are directly applicable to understanding the KDR receptor. For example, use of the murine FLK-1 receptor in methods which identify compounds that regulate the murine signal transduction pathway are directly applicable to the identification of compounds which may be used to regulate the human signal transduction pathway, that is, which regulate activity related to the KDR receptor. Thus, chemical compounds identified as inhibitors of KDR/FLK-1 in vitro, can be confirmed in suitable in vivo models. Both in vivo mouse and rat animal models have been demonstrated to be of excellent value for the examination of the clinical potential of agents acting on the KDR/FLK-1 induced signal transduction pathway.
Thus, in one aspect, this invention is directed to compounds that regulate, modulate and/or inhibit vasculogenesis and/or angiogenesis by affecting the enzymatic activity of the KDR/FLK-1 receptor and interfering with the signal transduced by KDR/FLK-1. In another aspect, the present invention is directed to compounds which regulate, modulate and/or inhibit the KDR/FLK-1 mediated signal transduction pathway as a therapeutic approach to the treatment of many kinds of solid tumors including, but not limited to, glioblastoma, melanoma and Kaposi""s sarcoma, and ovarian, lung, mammary, prostate, pancreatic, colon and epidermoid carcinoma. In addition, data suggest the administration of compounds which inhibit the KDR/Flk-1 mediated signal transduction pathway may also be used in the treatment of hemangioma, restenois and diabetic retinopathy.
A further aspect of this invention relates to the inhibition of vasculogenesis and angiogenesis by other receptor-mediated pathways, including the pathway comprising the flt-1 receptor.
Receptor tyrosine kinase mediated signal transduction is initiated by extracellular interaction with a specific growth factor (ligand), followed by receptor dimerization, transient stimulation of the intrinsic protein tyrosine kinase activity and autophosphorylation. Binding sites are thereby created for intracellular signal transduction molecules which leads to the formation of complexes with a spectrum of cytoplasmic signalling molecules that facilitate the appropriate cellular response, e.g., cell division and metabolic effects to the extracellular microenvironment. See, Schlessinger and Ullrich, 1992, Neuron, 9:1-20.
The close homology of the intracellular regions of KDR/FLK-1 with that of the PDGF-xcex2 receptor (50.3% homology) and/or the related flt-1 receptor indicates the induction of overlapping signal transduction pathways. For example, for the PDGF-xcex2 receptor, members of the src family (Twamley et al., 1993, Proc. Natl. Acad. Sci. USA, 90:7696-7700), phosphatidylinositol-3xe2x80x2-kinase (Hu et al., 1992, Mol. Cell. Biol., 12:981-990), phospholipase cxcex3 (Kashishian and Cooper, 1993, Mol. Cell. Biol., 4:49-51), ras-GTPase-activating protein, (Kashishian et al., 1992, EMBO J., 11:1373-1382), PTP-ID/syp (Kazlauskas et al., 1993, Proc. Natl. Acad. Sci. USA, 10 90:6939-6943), Grb2 (Arvidsson et al., 1994, Mol. Cell. Biol., 14:6715-6726), and the adapter molecules Shc and Nck (Nishimura et al., 1993, Mol. Cell. Biol., 13:6889-6896), have been shown to bind to regions involving different autophosphorylation sites. See generally, Claesson-Welsh, 1994, Prog. Growth Factor Res., 5:37-54. Thus, it is likely that signal transduction pathways activated by KDR/FLK-1 include the ras pathway (Rozakis et al., 1992, Nature, 360:689-692), the PI-3xe2x80x2-kinase, the src-mediated and the plcxcex3-mediated pathways. Each of these pathways may play a critical role in the angiogenic and/or vasculogenic effect of KDR/FLK-1 in endothelial cells. Consequently, a still further aspect of this invention relates to the use of the organic compounds described herein to modulate angiogenesis and vasculogenesis as such processes are controlled by these pathways.
Conversely, disorders related to the shrinkage, contraction or closing of blood vessels, such as restenosis, are also implicated and may be treated or prevented by the methods of this invention.
Fibrotic disorders refer to the abnormal formation of extracellular matrices. Examples of fibrotic disorders include hepatic cirrhosis and mesangial cell proliferative disorders. Hepatic cirrhosis is characterized by the increase in extracellular matrix constituents resulting in the formation of a hepatic scar. An increased extracellular matrix resulting in a hepatic scar can also be caused by a viral infection such as hepatitis. Lipocytes appear to play a major role in hepatic cirrhosis. Other fibrotic disorders implicated include atherosclerosis.
Mesangial cell proliferative disorders refer to disorders brought about by abnormal proliferation of mesangial cells. Mesangial proliferative disorders include various human renal diseases such as glomerulonephritis, diabetic nephropathy and malignant nephrosclerosis as well as such disorders as thrombotic microangiopathy syndromes, transplant rejection, and glomerulopathies. The RTK PDGFR has been implicated in the maintenance of mesangial cell proliferation. Floege et al., 1993, Kidney International 43:47S-54S.
Many cancers are cell proliferative disorders and, as noted previously, PKs have been associated with cell proliferative disorders. Thus, it is not surprising that PKs such as, for example, members of the RTK family have been associated with the development of cancer. Some of these receptors, like EGFR (Tuzi et al., 1991, Br. J. Cancer 63:227-233, Torp et al., 1992, APMIS 100:713-719) HER2/neu (Slamon et al., 1989, Science 244:707-712) and PDGF-R (Kumabe et al., 1992, Oncogene, 7:627-633) are over-expressed in many tumors and/or persistently activated by autocrine loops. In fact, in the most common and severe cancers these receptor over-expressions (Akbasak and Suner-Akbasak et al., 1992, J. Neurol. Sci., 111:119-133, Dickson et al., 1992, Cancer Treatment Res. 61:249-273, Korc et al., 1992, J. Clin. Invest. 90:1352-1360) and autocrine loops (Lee and Donoghue, 1992, J. Cell. Biol., 118:1057-1070, Korc et al., supra, Akbasak and Suner-Akbasak et al., supra) have been demonstrated. For example, EGFR has been associated with squamous cell carcinoma, astrocytoma, glioblastoma, head and neck cancer, lung cancer and bladder cancer. HER2 has been associated with breast, ovarian, gastric, lung, pancreas and bladder cancer. PDGFR has been associated with glioblastoma and melanoma as well as lung, ovarian and prostate cancer. The RTK c-met has also been associated with malignant tumor formation. For example, c-met has been associated with, among other cancers, colorectal, thyroid, pancreatic, gastric and hepatocellular carcinomas and lymphomas. Additionally c-met has been linked to leukemia. Over-expression of the c-met gene has also been detected in patients with Hodgkins disease and Burkitts disease.
IGF-IR, in addition to being implicated in nutritional support and in type-II diabetes, has also been associated with several types of cancers. For example, IGF-I has been implicated as an autocrine growth stimulator for several tumor types, e.g. human breast cancer carcinoma cells (Arteaga et al., 1989, J. Clin. Invest. 84:1418-1423) and small lung tumor cells (Macauley et al., 1990, Cancer Res., 50:2511-2517). In addition, IGF-I, while integrally involved in the normal growth and differentiation of the nervous system, also appears to be an autocrine stimulator of human gliomas. Sandberg-Nordqvist et al., 1993, Cancer Res. 53:2475-2478. The importance of IGF-IR and its ligands in cell proliferation is further supported by the fact that many cell types in culture (fibroblasts, epithelial cells, smooth muscle cells, T-lymphocytes, myeloid cells, chondrocytes and osteoblasts (the stem cells of the bone marrow)) are stimulated to grow by IGF-I. Goldring and Goldring, 1991, Eucaryotic Gene Expression, 1:301-326. In a series of recent publications, Baserga suggests that IGF-IR plays a central role in the mechanism of transformation and, as such, could be a preferred target for therapeutic interventions for a broad spectrum of human malignancies. Baserga, 1995, Cancer Res., 55:249-252, Baserga, 1994, Cell 79:927-930, Coppola et al., 1994, Mol. Cell. Biol., 14:4588-4595.
STKs have been implicated in many types of cancer including, notably, breast cancer (Cance, et al., Int. J. Cancer, 54:571-77 (1993)).
The association between abnormal PK activity and disease is not restricted to cancer. For example, RTKs have been associated with diseases such as psoriasis, diabetes mellitus, endometriosis, angiogenesis, atheromatous plaque development, Alzheimer""s disease, von Hippel-Lindau disease, epidermal hyperproliferation, neurodegenerative diseases, age-related macular degeneration and hemangiomas. For example, EGFR has been indicated in corneal and dermal wound healing. Defects in Insulin-R and IGF-1R are indicated in type-II diabetes mellitus. A more complete correlation between specific RTKs and their therapeutic indications is set forth in Plowman et al., 1994, DNandP 7:334-339.
As noted previously, not only RTKs but CTKs including, but not limited to, src, abl, fps, yes, fyn, lyn, lck, blk, hck, fgr and yrk (reviewed by Bolen et al., 1992, FASEB J., 6:3403-3409) are involved in the proliferative and metabolic signal transduction pathway and thus could be expected, and have been shown, to be involved in many PTK-mediated disorders to which the present invention is directed. For example, mutated src (v-src) has been shown to be an oncoprotein (pp60v-src) in chicken. Moreover, its cellular homolog, the proto-oncogene pp60c-src transmits oncogenic signals of many receptors. Over-expression of EGFR or HER2/neu in tumors leads to the constitutive activation of pp60c src, which is characteristic of malignant cells but absent in normal cells. On the other hand, mice deficient in the expression of c-src exhibit an osteopetrotic phenotype, indicating a key participation of c-src in osteoclast function and a possible involvement in related disorders.
Similarly, Zap70 has been implicated in T-cell signaling which may relate to autoimmune disorders.
STKs have been associated with inflamation, autoimmune disease, immunoresponses, and hyperproliferation disorders such as restenosis, fibrosis, psoriasis, osteoarthritis and rheumatoid arthritis.
PKs have also been implicated in embryo implantation. Thus, the compounds of this invention may provide an effective method of preventing such embryo implantation and thereby be useful as birth control agents.
Finally, both RTKs and CTKs are currently suspected as being involved in hyperimmune disorders.
A method for identifying a chemical compound that modulates the catalytic activity of one or more of the above discussed protein kinases is another aspect of this invention. The method involves contacting cells expressing the desired protein kinase with a compound of this invention (or its salt or prodrug) and monitoring the cells for any effect that the compound has on them. The effect may be any observable, either to the naked eye or through the use of instrumentation, change or absence of change in a cell phenotype. The change or absence of change in the cell phenotype monitored may be, for example, without limitation, a change or absence of change in the catalytic activity of the protein kinase in the cells or a change or absence of change in the interaction of the protein kinase with a natural binding partner.
Examples of the effect of a number of exemplary compounds of this invention on several PTKs are shown in Tables 1 and 2 and in the Biological Examples section, below. The compounds and data presented are not to be construed as limiting the scope of this invention in any manner whatsoever.
5. PHARMACEUTICAL COMPOSITIONS AND USE
A compound of the present invention, a prodrug thereof or a physiologically acceptable salt of either the compound or its prodrug, can be administered as such to a human patient or can be administered in pharmaceutical compositions in which the foregoing materials are mixed with suitable carriers or excipient(s). Techniques for formulation and administration of drugs may be found in xe2x80x9cRemington""s Pharmacological Sciences,xe2x80x9d Mack Publishing Co., Easton, Pa., latest edition.
Routes of Administration
As used herein, xe2x80x9cadministerxe2x80x9d or xe2x80x9cadministrationxe2x80x9d refers to the delivery of a compound, salt or prodrug of the present invention or of a pharmaceutical composition containing a compound, salt or prodrug of this invention to an organism for the purpose of prevention or treatment of a PK-related disorder.
Suitable routes of administration may include, without limitation, oral, rectal, transmucosal or intestinal administration or intramuscular, subcutaneous, intramedullary, intrathecal, direct intraventricular, intravenous, intravitreal, intraperitoneal, intranasal, or intraocular injections. The preferred routes of administration ary oral and parenteral.
Alternatively, one may administer the compound in a local rather than systemic manner, for example, via injection of the compound directly into a solid tumor, often in a depot or sustained release formulation.
Furthermore, one may administer the drug in a targeted drug delivery system, for example, in a liposome coated with tumor-specific specific antibody. The liposomes will be targeted to and taken up selectively by the tumor.
Composition/Formulation
Pharmaceutical compositions of the present invention may be manufactured by processes well known in the art, e.g., by means of conventional mixing, dissolving, granulating, dragee-making, levigating, emulsifying, encapsulating, entrapping or lyophilizing processes.
Pharmaceutical compositions for use in accordance with the present invention may be formulated in conventional manner using one or more physiologically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the active compounds into preparations which can be used pharmaceutically. Proper formulation is dependent upon the route of administration chosen.
For injection, the compounds of the invention may be formulated in aqueous solutions, preferably in physiologically compatible buffers such as Hanks"" solution, Ringer""s solution, or physiological saline buffer. For transmucosal administration, penetrants appropriate to the barrier to be permeated are used in the formulation. Such penetrants are generally known in the art.
For oral administration, the compounds can be formulated by combining the active compounds with pharmaceutically acceptable carriers well known in the art. Such carriers enable the compounds of the invention to be formulated as tablets, pills, lozenges, dragees, capsules, liquids, gels, syrups, slurries, suspensions and the like, for oral ingestion by a patient. Pharmaceutical preparations for oral use can be made using a solid excipient, optionally grinding the resulting mixture, and processing the mixture of granules, after adding other suitable auxiliaries if desired, to obtain tablets or dragee cores. Useful excipients are, in particular, fillers such as sugars, including lactose, sucrose, mannitol, or sorbitol, cellulose preparations such as, for example, maize starch, wheat starch, rice starch and potato starch and other materials such as gelatin, gum tragacanth, methyl cellulose, hydroxypropylmethylcellulose, sodium carboxymethylcellulose, and/or polyvinylpyrrolidone (PVP). If desired, disintegrating agents may be added, such as cross-linked polyvinyl pyrrolidone, agar, or alginic acid. A salt such as sodium alginate may also be used.
Dragee cores are provided with suitable coatings. For this purpose, concentrated sugar solutions may be used which may optionally contain gum arabic, talc, polyvinyl pyrrolidone, carbopol gel, polyethylene glycol, and/or titanium dioxide, lacquer solutions, and suitable organic solvents or solvent mixtures. Dyestuffs or pigments may be added to the tablets or dragee coatings for identification or to characterize different combinations of active compound doses.
Pharmaceutical compositions which can be used orally include push-fit capsules made of gelatin, as well as soft, sealed capsules made of gelatin and a plasticizer, such as glycerol or sorbitol. The push-fit capsules can contain the active ingredients in admixture with a filler such as lactose, a binder such as starch, and/or a lubricant such as talc or magnesium stearate and, optionally, stabilizers. In soft capsules, the active compounds may be dissolved or suspended in suitable liquids, such as fatty oils, liquid paraffin, or liquid polyethylene glycols. Stabilizers may be added in these formulations, also.
For administration by inhalation, the compounds for use according to the present invention are conveniently delivered in the form of an aerosol spray using a pressurized pack or a nebulizer and a suitable propellant, e.g., without limitation, dichlorodifluoromethane, trichlorofluoromethane, dichlorotetrafluoroethane or carbon dioxide. In the case of a pressurized aerosol, the dosage unit may be controlled by providing a valve to deliver a metered amount. Capsules and cartridges of, for example, gelatin for use in an inhaler or insufflator may be formulated containing a powder mix of the compound and a suitable powder base such as lactose or starch.
The compounds may also be formulated for parenteral administration, e.g., by bolus injection or continuous infusion. Formulations for injection may be presented in unit dosage form, e.g., in ampoules or in multi-dose containers, with an added preservative. The compositions may take such forms as suspensions, solutions or emulsions in oily or aqueous vehicles, and may contain formulating materials such as suspending, stabilizing and/or dispersing agents.
Pharmaceutical compositions for parenteral administration include aqueous solutions of a water soluble form, such as, without limitation, a salt, of the active compound. Additionally, suspensions of the active compounds may be prepared in a lipophilic vehicle. Suitable lipophilic vehicles include fatty oils such as sesame oil, synthetic fatty acid esters such as ethyl oleate and triglycerides, or materials such as liposomes. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension, such as sodium carboxymethyl cellulose, sorbitol, or dextran. Optionally, the suspension may also contain suitable stabilizers and/or agents that increase the solubility of the compounds to allow for the preparation of highly concentrated solutions.
Alternatively, the active ingredient may be in powder form for constitution with a suitable vehicle, e.g., sterile, pyrogen-free water, before use.
The compounds may also be formulated in rectal compositions such as suppositories or retention enemas, using, e.g., conventional suppository bases such as cocoa butter or other glycerides.
In addition to the fomulations described previously, the compounds may also be formulated as depot preparations. Such long acting formulations may be administered by implantation (for example, subcutaneously or intramuscularly) or by intramuscular injection. A compound of this invention may be formulated for this route of administration with suitable polymeric or hydrophobic materials (for instance, in an emulsion with a pharamcologically acceptable oil), with ion exchange resins, or as a sparingly soluble derivative such as, without limitation, a sparingly soluble salt.
A non-limiting example of a pharmaceutical carrier for the hydrophobic compounds of the invention is a cosolvent system comprising benzyl alcohol, a nonpolar surfactant, a water-miscible organic polymer and an aqueous phase such as the VPD co-solvent system. VPD is a solution of 3% w/v benzyl alcohol, 8% w/v of the nonpolar surfactant Polysorbate 80(trademark), and 65% w/v polyethylene glycol 300, made up to volume in absolute ethanol. The VPD co-solvent system (VPD:D5W) consists of VPD diluted 1:1 with a 5% dextrose in water solution. This co-solvent system dissolves hydrophobic compounds well, and itself produces low toxicity upon systemic administration. Naturally, the proportions of such a co-solvent system may be varied considerably without destroying its solubility and toxicity characteristics. Furthermore, the identity of the co-solvent components may be varied: for example, other low-toxicity nonpolar surfactants may be used instead of Polysorbate 80(trademark), the fraction size of polyethylene glycol may be varied, other biocompatible polymers may replace polyethylene glycol, e.g., polyvinyl pyrrolidone, and other sugars or polysaccharides may substitute for dextrose.
Alternatively, other delivery systems for hydrophobic pharmaceutical compounds may be employed. Liposomes and emulsions are well known examples of delivery vehicles or carriers for hydrophobic drugs. In addtion, certain organic solvents such as dimethylsulfoxide also may be employed, although often at the cost of greater toxicity.
Additionally, the compounds may be delivered using a sustained-release system, such as semipermeable matrices of solid hydrophobic polymers containing the therapeutic agent. Various sustained-release materials have been established and are well known by those skilled in the art. Sustained-release capsules may, depending on their chemical nature, release the compounds for a few weeks up to over 100 days. Depending on the chemical nature and the biological stability of the therapeutic reagent, additional strategies for protein stabilization may be employed.
The pharmaceutical compositions herein also may comprise suitable solid or gel phase carriers or excipients. Examples of such carriers or excipients include, but are not limited to, calcium carbonate, calcium phosphate, various sugars, starches, cellulose derivatives, gelatin, and polymers such as polyethylene glycols.
Many of the PK modulating compounds of the invention may be provided as physiologically acceptable salts wherein the claimed compound may form the negatively or the positively charged species. Examples of salts in which the compound forms the positively charged moiety include, without limitation, quaternary ammonium (defined elsewhere herein), salts such as the hydrochloride, sulfate, carbonate, lactate, tartrate, maleate, succinate wherein the nitrogen atom of the quaternary ammonium group is a nitrogen of the selected compound of this invention which has reacted with the appropriate acid. Salts in which a compound of this invention forms the negatively charged species include, without limitation, the sodium, potassium, calcium and magnesium salts formed by the reaction of a carboxylic acid group in the compound with an appropriate base (e.g. sodium hydroxide (NaOH), potassium hydroxide (KOH), Calcium hydroxide (Ca(OH)2), etc.).
Dosage
Pharmaceutical compositions suitable for use in the present invention include compositions wherein the active ingredients are contained in an amount sufficient to achieve the intended purpose, i.e., the modulation of PK activity or the treatment or prevention of a PK-related disorder.
More specifically, a therapeutically effective amount means an amount of compound effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated.
Determination of a therapeutically effective amount is well within the capability of those skilled in the art, especially in light of the detailed disclosure provided herein.
For any compound used in the methods of the invention, the therapeutically effective amount or dose can be estimated initially from cell culture assays. Then, the dosage can be formulated for use in animal models so as to achieve a circulating concentration range that includes the IC50 as determined in cell culture (i.e., the concentration of the test compound which achieves a half-maximal inhibition of the PK activity). Such information can then be used to more accurately determine useful doses in humans.
Toxicity and therapeutic efficacy of the compounds described herein can be determined by standard pharmaceutical procedures in cell cultures or experimental animals, e.g., by determining the IC50 and the LD50 (both of which are discussed elsewhere herein) for a subject compound. The data obtained from these cell culture assays and animal studies can be used in formulating a range of dosage for use in humans. The dosage may vary depending upon the dosage form employed and the route of administration utilized. The exact formulation, route of administration and dosage can be chosen by the individual physician in view of the patient""s condition. (See e.g., Fingl, et al., 1975, in xe2x80x9cThe Pharmacological Basis of Therapeuticsxe2x80x9d, Ch. 1 p.1).
Dosage amount and interval may be adjusted individually to provide plasma levels of the active species which are sufficient to maintain the kinase modulating effects. These plasma levels are referred to as minimal effective concentrations (MECs). The MEC will vary for each compound but can be estimated from in vitro data, e.g., the concentration necessary to achieve 50-90% inhibition of a kinase may be ascertained using the assays described herein. Dosages necessary to achieve the MEC will depend on individual characteristics and route of administration. HPLC assays or bioassays can be used to determine plasma concentrations.
Dosage intervals can also be determined using MEC value. Compounds should be administered using a regimen that maintains plasma levels above the MEC for 10-90% of the time, preferably between 30-90% and most preferably between 50-90%.
In cases of local administration or selective uptake, the effective local concentration of the drug may not be related to plasma concentration and other procedures known in the art may be employed to determine the correct dosage amount and interval.
The amount of a composition administered will, of course, be dependent on the subject being treated, the severity of the affliction, the manner of administration, the judgment of the prescribing physician, etc.
Packaging
The compositions may, if desired, be presented in a pack or dispenser device, such as an FDA approved kit, which may contain one or more unit dosage forms containing the active ingredient. The pack may for example comprise metal or plastic foil, such as a blister pack. The pack or dispenser device may be accompanied by instructions for administration. The pack or dispenser may also be accompanied by a notice associated with the container in a form prescribed by a governmental agency regulating the manufacture, use or sale of pharmaceuticals, which notice is reflective of approval by the agency of the form of the compositions or of human or veterinary administration. Such notice, for example, may be of the labeling approved by the U.S. Food and Drug Administration for prescription drugs or of an approved product insert. Compositions comprising a compound of the invention formulated in a compatible pharmaceutical carrier may also be prepared, placed in an appropriate container, and labeled for treatment of an indicated condition. Suitable conditions indicated on the label may include treatment of a tumor, inhibition of angiogenesis, treatment of fibrosis, diabetes, and the like.
6. SYNTHESIS
The compounds of this invention, as well as the precursor 2-oxindoles and aldehydes, may be readily synthesized using techniques well known in the chemical arts. It will be appreciated by those skilled in the art that other synthetic pathways for forming the compounds of the invention are available and that the following is offered by way of example and not limitation.
A. General Synthetic Procedure
The following general methodology may be employed to prepare the compounds of this invention:
The appropriately substituted 2-oxindole (1 equiv.), the appropriately substituted aldehyde (1.2 equiv.) and piperidine (0.1 equiv.) are mixed with ethanol (1-2 ml/mmol 2-oxindole) and the mixture is then heated at 90xc2x0 C. for 3 to 5 hours After cooling, the reaction mixture is concentrated and acidified to pH 3. The precipitate that forms is filtered, washed with water to pH 7 and then cold ethanol, ethyl acetate and/or hexane and vacuum dried to yield the target compound. The product may optionally be further purified by chromatography.
B. 2-oxindoles
The following examples are representative syntheses of 2-oxindole precursors to the compounds of this invention. These 2-oxindoles will form the claimed compounds by reaction with an appropriately substituted pyrrole aldehyde using the above general synthetic procedure or the procedures exemplified in section C, below. It is to be understood that the following syntheses are not to be construed as limiting either with regard to synthetic approach or to the oxindoles whose syntheses are exemplified.
5-Amino-2-oxindole
5-Nitro-2-oxindole (6.3 g) was hydrogenated in methanol over 10% palladium on carbon to give 3.0 g (60% yield) of the title compound as a white solid.
5-Bromo-2-oxindole
2-Oxindole (1.3 g) in 20 mL acetonitrile was cooled to xe2x88x9210xc2x0 C. and 2.0 g N-bromosuccinimide was slowly added with stirring. The reaction was stirred for 1 hour at xe2x88x9210xc2x0 C. and 2 hours at 0xc2x0 C. The precipitate was collected, washed with water and dried to give 1.9 g (90% yield) of the title compound.
4-Methyl-2-oxindole
Diethyl oxalate (30 mL) in 20 mL of dry ether was added with stirring to 19 g of potassium ethoxide suspended in 50 mL of dry ether. The mixture was cooled in an ice bath and 20 mL of 3-nitro-o-xylene in 20 mL of dry ether was slowly added. The thick dark red mixture was heated to reflux for 0.5 hr, concentrated to a dark red solid, and treated with 10% sodium hydroxide until almost all of the solid dissolved. The dark red mixture was treated with 30% hydrogen peroxide until the red color changed to yellow. The mixture was treated alternately with 10% sodium hydroxide and 30% hydrogen peroxide until the dark red color was no longer present. The solid was filtered off and the filtrate acidified with 6 N hydrochloric acid. The resulting precipitate was collected by vacuum filtration, washed with water, and dried under vacuum to give 9.8 g (45% yield) of 2-methyl-6-nitrophenylacetic acid as an off-white solid. The solid was hydrogenated in methanol over 10% palladium on carbon to give 9.04 g of the title compound as a white solid.
7-Bromo-5-chloro-2-oxindole
5-Chloro-2-oxindole (16.8 g) and 19.6 g of N-bromosuccinimide were suspended in 140 mL of acetonitrile and refluxed for 3 hours. Thin layer chromatography (silica, ethyl acetate) at 2 hours of reflux showed 5-chloro-2-oxindole or N-bromosuccinimide (Rf 0.8), product (Rf 0.85) and a second product (Rf 0.9) whose proportions did not change after another hour of reflux. The mixture was cooled to 10xc2x0 C., the precipitate was collected by vacuum filtration, washed with 25 mL of ethanol and sucked dry for 20 minutes in the funnel to give 14.1 g of wet product (56% yield). The solid was suspended in 200 mL of denatured ethanol and slurry-washed by stirring and refluxing for 10 minutes. The mixture was cooled in an ice bath to 10xc2x0 C. The solid product was collected by vacuum filtration, washed with 25 mL of ethanol and dried under vacuum at 40xc2x0 C. to give 12.7 g (51% yield) of 7-bromo-5-chloro-2-oxindole.
5-Fluoro-2-oxindole
5-Fluoroisatin (8.2 g) was dissolved in 50 mL of hydrazine hydrate and refluxed for 1.0 hr. The reaction mixtures were then poured in ice water. The precipitate was then filtered, washed with water and dried in a vacuum oven to afford the title compound.
5-Nitro-2-oxindole
2-Oxindole (6.5 g) was dissolved in 25 mL concentrated sulfuric acid and the mixture maintained at xe2x88x9210 to xe2x88x9215xc2x0 C. while 2.1 mL of fuming nitric acid was added dropwise. After the addition of the nitric acid the reaction mixture was stirred at 0xc2x0 C. for 0.5 hr and poured into ice-water. The precipitate was collected by filtration, washed with water and crystallized from 50% acetic acid. The crystalline product was then filtered, washed with water and dried under vacuum to give 6.3 g (70%) of 5-nitro-2-oxindole.
5-Iodo-2-oxindole
2-Oxindole (82.9 g) was suspended in 630 mL of acetic acid with mechanical stirring and the mixture cooled to 10xc2x0 C. in an ice water bath. Solid N-iodosuccinimide (175 g) was added in portions over 10 minutes. After the addition was complete the mixture was stirred for 1.0 hour at 10xc2x0 C. The suspended solid, which had always been present, became very thick at this time. The solid was collected by vacuum filtration, washed with 100 mL of 50% acetic acid in water and then with 200 mL of water and sucked dry for 20 minutes in the funnel. The product was dried under vacuum to give 93.5 g (36%) of 5-iodo-2-oxindole containing about 5% 2-oxindole by proton NMR.
5-Methyl-2-oxindole
5-Methylisatin (15.0 g) and 60 mL of hydrazine hydrate were heated at 140 to 160xc2x0 C. for 4 hours. Thin layer chromatography (ethyl acetate:hexane 1:2, silica gel) showed no starting material remaining. The reaction mixture was cooled to room temperature, poured into 300 mL of ice water and acidified to pH 2 with 6 N hydrochloric acid. After standing at room temperature for 2 days the precipitate was collected by vacuum filtration, washed with water and dried under vacuum to give 6.5 g (47% yield) of 5-methyl-2-oxindole.
5-Bromo-4-methyloxindole and 5,7-Dibromo-4-methyloxindole
4-Methyl-2-oxindole (5 g) in 40 mL of acetonitrile was treated with 7.26 g of N-bromosuccinimide and stirred at room temperature for 4 hours. Thin layer chromatography (ethyl acetate:hexane 1:2, silica gel) showed a mixture of 5-bromo (Rf 0.3) and 5,7-dibromo (Rf 0.5) products. Another 7.26 g of N-bromosuccinimide was added and the mixture stirred for 4 additional hours. The solid was collected by vacuum filtration, washed with 20 mL of acetonitrile and dried to give a 1:1 mixture of mono and dibromo compounds. The filtrate was concentrated and chromatographed on silica gel (ethyl acetate:hexane (1:2)) to give 1.67 g of 5-bromo-4-methyl-2-oxindole as a beige solid. The remaining 1:1 mixture of solids was recrystallized twice from glacial acetic acid to give 3.2 g of 5,7-dibromo-4-methyl-2-oxindole as a light orange solid. The filtrates from this material were chromatographed as above to give 0.6 g of 5-bromo-4-methyl-2-oxindole and 0.5 g of 5,7-dibromo-4-methyl-2-oxindole.
6-Fluoro-2-oxindole
Sodium hydride (2.6 g) and 14.5 g of dimethylmalonate was stirred and heated to 100xc2x0 C. in 160 mL dimethylsulfoxide for 1.0 hour. The mixture was cooled to room temperature, 7.95 g of 2,5-difluoronitrobenzene were added and the mixture was stirred for 30 minutes. The mixture was then heated to 100xc2x0 C. for 1.0 hour, cooled to room temperature and poured into 400 mL of saturated ammonium chloride solution. The mixture was extracted with 200 mL of ethyl acetate and the organic layer washed with brine, dried over anhydrous sodium sulfate and concentrated under vacuum. The residue was crystallized from methanol to give 24.4 g (80% yield) of dimethyl 4-fluoro-2-nitrophenylmalonate as a white solid, Rf 0.2 on thin layer chromatography (ethyl acetate:hexane 1:6, silica gel). The filtrate was concentrated and chromatographed on a column of silica gel (ethyl acetate:hexane 1:8) to give an additional 5.03 g of dimethyl 4-fluoro-2-nitrophenylmalonate, for a total of 29.5 g (96% yield).
Dimethyl 4-fluoro-2-nitrophenylmalonate (5.0 g) was refluxed in 20 mL of 6 N hydrochloric acid for 24 hours. The reaction was cooled and the white solid collected by vacuum filtration, washed with water and dried to give 3.3 g (87% yield) of 4-fluoro-2-nitrophenylacetic acid, Rf 0.6 on thin layer chromatography (ethyl acetate:hexane 1:2, silica gel).
4-Fluoro-2-nitrophenylacetatic acid (3.3 g) dissolved in 15 mL of acetic acid was hydrogenated over 0.45 g of 10% palladium on carbon at 60 psi H2 for 2 hours. The catalyst was removed by filtration and washed with 15 mL of methanol. The combined filtrates were concentrated and diluted with water. The precipitate was collected by vacuum filtration, washed with water and dried to give 1.6 g (70% yield) of 6-fluoro-2-oxindole, Rf 0.24 on thin layer chromatography. The filtrate was concentrated to give a purple solid with an NNM spectrum similar to the first crop. Chromatography of the purple solid (ethyl acetate:hexane 1:2, silica gel) gave a second crop of 6-fluoro-2-oxindole as a white solid.
5-Aminosulfonyl-2-oxindole
To a 100 mL flask charged with 27 mL of chlorosulfonic acid was added slowly 13.3 g of 2-oxindole. The reaction temperature was maintained below 30xc2x0 C. during the addition. After the addition, the reaction mixture was stirred at room temperature for 1.5 hr, heated to 68xc2x0 C. for 1 hr, cooled, and poured into water. The precipitate was washed with water and dried in a vacuum oven to give 11.0 g of 5-chlorosulfonyl-2-oxindole (50% yield) which was used without further purification.
5-Chlorosulfonyl-2-oxindole (2.1 g) was added to 10 mL of ammonium hydroxide in 10 mL of ethanol and stirred at room temperature overnight. The mixture was concentrated and the solid collected by vacuum filtration to give 0.4 g (20% yield) of the title compound as an off-white solid.
5-Methylaminosulfonyl-2-oxindole
A suspension of 3.38 g of 5-chlorosulfonyl-2-oxindole in 10 mL 2 M methylamine in tetrahydrofuran was stirred at room temperature for 4 hours during which time a white solid formed. The precipitate was collected by vacuum filtration, washed twice with 5 mL of water and dried under vacuum at 40xc2x0 C. overnight to give 3.0 g (88% yield) of 5-methylaminosulfonyl-2-oxindole.
5-(4-Trifluoromethylphenylaminosulfonyl)-2-oxindole
A suspension of 2.1 g of 5-chlorosulfonyl-2-oxindole, 1.6 g of 4-trifluoromethylaniline and 1.4 g of pyridine in 20 mL of dichloromethane was stirred at room temperature for 4 hours. The precipitate which formed was collected by vacuum filtration, washed twice with 5 mL of water and dried under vacuum at 40xc2x0 C. overnight to give 2.4 g of crude product containing some impurities by thin layer chromatography. The crude product was chromatographed on silica gel eluting with ethyl acetate:hexane (1:2) to give 1.2 g (37% yield) of 5-(4-trifluoromethylphenylaminosulfonyl)-2-oxindole.
5-(Morpholinosulfonyl)-2-oxindole
A suspension of 2.3 g of 5-chlorosulfonyl-2-oxindole and 2.2 g of morpholine in 50 mL of dichloromethane was stirred at room temperature for 3 hours. The white precipitate was collected by vacuum filtration, washed with ethyl acetate and hexane and dried under vacuum at 40xc2x0 C. overnight to give 2.1 g (74% yield) of 5-(morpholinosulfonyl)-2-oxindole.
6-Trifluoromethyl-2-oxindole
Dimethylsulfoxide (330 mL) was added to 7.9 g of sodium hydride followed by dropwise addition of 43.6 g diethyloxalate. The mixture was heated to 100xc2x0 C. for 1.0 hour and cooled to room temperature. 2-Nitro-4-trifluoromethyltoluene (31.3 g) was added, the reaction stirred for 30 minutes at room temperature and then heated to 100xc2x0 C. for 1 hour. The reaction was cooled and poured into a mixture of saturated aqueous ammonium chloride, ethyl acetate and hexane. The organic layer was washed with saturated ammonium chloride, water and brine, dried, and concentrated to give dimethyl 2-(2-nitro-4-trifluoromethylphenyl)malonate.
The diester was dissolved in a mixture of 6.4 g of lithium chloride and 2.7 mL of water in 100 mL of dimethylsulfoxide and heated to 100xc2x0 C. for 3 hours. The reaction was cooled and poured into a mixture of ethyl acetate and brine. The organic phase was washed with brine, dried with sodium sulfate, concentrated and chromatographed on silica gel (10% ethyl acetate in hexane). The fractions containing product were evaporated to give 25.7 g of methyl 2-nitro-4-trifluoromethylphenylacetate.
Methyl 2-nitro-4-trifluoromethylphenylacetate (26 mg) was hydrogenated over 10% palladium on carbon and then heated at 100xc2x0 C. for 3 hours. The catalyst was removed by filtration and the solvent evaporated to give the title compound.
5-(2-Chloroethyl)oxindole
5-Chloroacetyl-2-oxindole(4.18 g) in 30 mL of trifluoroacetic acid in an ice bath was treated with 4.65 g of triethylsilane and stirred at room temperature for 3 hours. The mixture was poured into 150 mL of water and the precipitate collected by vacuum filtration, washed with 50 mL of water and dried to give 2.53 g (65% yield) of 5-(2-chloroethyl)-2-oxindole as a reddish-brown solid.
5-Methoxycarbonyl-2-oxindole
5-Iodo-2-oxindole (17 g) was refluxed with 2 g of palladium diacetate, 18.2 g of triethylamine, 150 mL of methanol, 15 mL of dimethylsulfoxide and 2.6 g of DPPP in an atmosphere saturated with carbon monoxide. After 24 hours, the reaction was filtered to remove the catalyst and the filtrate concentrated. The concentrate was chromatographed on silica gel (30% ethyl acetate in hexane). The fractions containing product were concentrated and allowed to stand. The precipitated product was collected by vacuum filtration to give 0.8 g (7%) of the title compound as an off-white solid.
4-Carboxy-2-oxindole
A solution of trimethylsilyldiazomethane in hexane (2 M) was added dropwise to a solution of 2.01 g of 2-chloro-3-carboxynitrobenzene in 20 mL methanol at room temperature until no further gas evolution occurred. The excess trimethylsilyldiazomethane was quenched with acetic acid. The reaction mixture was dried by rotary pump and the residue was further dried in a vacuum oven overnight. The product (2-chloro-3-methoxycarbonylnitrobenzene) was pure enough for the following reaction.
Dimethyl malonate (6.0 mL) was added to an ice-cold suspension of 2.1 g of sodium hydride in 15 mL of DMSO. The reaction mixture was then stirred at 100xc2x0 C. for 1.0 h and then cooled to room temperature. 2-Chloro-3-methoxycarbonylnitrobenzene (2.15 g) was added to the above mixture in one portion and the mixture was heated to 100xc2x0 C. for 1.5 h. The reaction mixture was then cooled to room temperature and poured into ice water, acidified to pH 5, and extracted with ethyl acetate. The organic layer was washed with brine, dried over anhydrous sodium sulfate and concentrated to give 3.0 g of the dimethyl 2-methoxycarbonyl-6-nitrophenylmalonate.
Dimethyl 2-methoxycarbonyl-6-nitrophenylmalonate (3.0 g) was refluxed in 50 mL of 6 N hydrochloric acid overnight. The mixture was concentrated to dryness and refluxed for 2 hours with 1.1 g of tin(II) chloride in 20 mL of ethanol. The mixture was filtered through Celite, concentrated and chromatographed on silica gel (ethyl acetate:hexane:acetic acid) to give 0.65 g (37% yield) of 4-carboxy-2-oxindole as a white solid.
5-Carboxy-2-oxindole
2-Oxindole (6.7 g) was added to a stirred suspension of 23 g of aluminum chloride in 30 mL of dichloroethane in an ice bath. Chloroacetyl chloride (11.3 g) was slowly added and hydrogen chloride gas was evolved. After ten minutes of stirring, the reaction was warmed at 40 to 50xc2x0 C. for 1.5 hours. Thin layer chromatography (ethyl acetate, silica gel) showed no remaining starting material. The mixture was cooled to room temperature and poured into ice water. The precipitate was collected by vacuum filtration, washed with water and dried under vacuum to give 10.3 g (98%) of 5-chloroacetyl-2-oxindole as an off-white solid.
A suspension of 9.3 g of 5-chloroacetyl-2-oxindole was stirred in 90 mL pyridine at 80 to 90xc2x0 C. for 3 hours then cooled to room temperature. The precipitate was collected by vacuum filtration and washed with 20 mL ethanol. The solid was dissolved in 90 mL 2.5 N sodium hydroxide and stirred at 70 to 80xc2x0 C. for 3 hours. The mixture was cooled to room temperature and acidified to pH 2 with 0.5 N hydrochloric acid. The precipitate was collected by vacuum filtration and washed thoroughly with water to give crude 5-carboxy-2-oxindole as a dark brown solid. After standing overnight the filtrate yielded 2 g of 5-carboxy-2-oxindole as a yellow solid. The crude dark brown product was dissolved in hot methanol, the insoluble material removed by filtration and the filtrate concentrated to give 5.6 g of 5-carboxy-2-oxindole as a brown solid. The combined yield was 97%.
5-Carboxyethyl-2-oxindole
5-Cyanoethyl-2-oxindole (4.02 g) in 10 mL of water containing 25 mL of concentrated hydrochloric acid was refluxed for 4 hours. The mixture was cooled, water added and the resulting solid collected by vacuum filtration, washed with water and dried to give 1.9 g (44% yield) of the title compound as a yellow solid.
5-Iodo-4-methyl-2-oxindole
To 2 g of 4-methyl-2-oxindole in 40 mL of glacial acetic acid in an ice bath was added 3.67 g N-iodosuccinimide. The mixture was stirred for 1 hour, diluted with 100 mL 50% acetic acid in water and filtered. The resulting white solid was dried under high vacuum to give 3.27 g (88% yield) of the title compound as an off-white solid.
5-Chloro-4-methyl-2-oxindole
A suspension of 3.0 g of 4-methyl-2-oxindole was stirred in 50 mL of acetonitrile at room temperature while 3.3 g of N-chlorosuccinimide was added in portions. Trifluoroacetic acid (1 mL) was then added. The suspension was stirred at room temperature for 3 days during which time solid was always present. The white solid was collected by vacuum filtration, washed with a small amount of cold acetone and dried overnight in a vacuum oven at 40xc2x0 C. to give 2.5 g (68%) of 5-chloro-4-methyl-2-oxindole.
5-Butyl-2-oxindole
Triethylsilane (2.3 g) was added to 2 g 4-butanoyl-2-oxindole in 20 mL of trifluoroacetic acid at room temperature and the solution stirred for 3 hours. The reaction was poured into ice water to give a red oil which solidified after standing. The solid was collected by vacuum filtration, washed with water and hexane and dried to give 1.7 g (91% yield) of the title compound as an off-white solid.
5-Ethyl-2-oxindole
To 5-Acetyl-2-oxindole (2 g) in 15 mL of trifluoroacetic acid in an ice bath was slowly added 1.8 g of triethylsilane; the reaction was then stirred at room temperature for 5 hours. One mL of triethylsilane was added and the stirring continued overnight. The reaction mixture was poured into ice water and the resulting precipitate collected by vacuum filtration, washed copiously with water and dried under vacuum to give 1.3 g (71% yield) of the title compound as a yellow solid.
5-(Morpholin-4-ethyl)-2-oxindole
5-Chloroethyl-2-oxindole (2.3 g), 1.2 mL of morpholine and 1.2 mL of diisopropylethylamine were heated overnight at 100xc2x0 C. in 10 mL of dimethylsulfoxide. The mixture ws cooled, poured into water and extacted with ethyl acetate. The organic layer was washed with brine, dried and evaporated. The residue was chromatographed on silica gel (5% methanol in chloroform) to give 0.9 g (31%) of the title compound as a white solid.
5-(4-Methoxycarbonylbenzamido)-2-oxindole
A mixture of 82.0 mg 5-amino-2-oxindole and 131.0 mg 4-methoxycarbonylbenzoyl chloride in pyridine was stirred at room temperature for 3 hr and poured into ice water. The precipitate was filtered, washed with water and dried in a vacuum oven to give 138.0 mg of 5-(4-methoxycarbonylbenzamido)-2-oxindole (81% yield).
5-(4-Carboxybenzamido)-2-oxindole
5-(4-Methoxycarbonylbenzamido)-2-oxindole (0.9 g) and 0.4 g of sodium hydroxide in 25 mL of methanol were refluxed for 3 hours. The mixture was concentrated, water added, and the mixture acidified with 6 N hydrochloric acid. The precipitate was collected by vacuum filtration to give 0.75 g (87%) of the title compound as a white solid.
5-Methoxy-2-oxindole
Chloral hydrate (9.6 g) was dissolved in 200 mL of water containing 83 g of sodium sulfate. The solution was warmed to 60xc2x0 C., a solution of 11.4 g of hydroxylamine hydrochloride in 50 mL of water was added and the mixture was held at 60xc2x0 C. In a separate flask, 6.4 g of 4-anisidine and 4.3 mL of concentrated hydrochloric acid in 80 mL of water was warmed to 80xc2x0 C. The first solution was added to the second and the mixture refluxed for 2 minutes after which it was cooled slowly to room temperature and then cooled in an ice bath. The tan precipitate was collected by vacuum filtration, washed with water and dried under vacuum to give 8.6 g (85% yield) of N-(2-hydroximinoacetyl)anisidine.
Concentrated sulfuric acid (45 mL) containing 5 mL of water was warmed to 60xc2x0 C. and 8.6 g of N-(2-hydroximinoacetyl)anisidine was added in one portion. The stirred mixture was heated to 93xc2x0 C. for 10 minutes and then allowed to cool to room temperature. The mixture was poured into 500 g of ice and extracted 3 times with ethyl acetate. The combined extracts were dried over anhydrous sodium sulfate and concentrated to give 5.1 g (65% yield) of 5-methoxyisatin as a dark red solid. 5-Methoxyisatin (5.0 g) and 30 mL of hydrazine hydrate were heated to reflux for 15 minutes. The reaction mixture was cooled to room temperature and 50 mL of water was added. The mixture was extracted 3 times with 25 mL of ethyl acetate each time, the organic layers combined, dried over anhydrous sodium sulfate and concentrated to give a yellow solid. The solid was stirred in ethyl acetate and 1.1 g of insoluble material was removed by vacuum filtration and saved. This material proved to be 2-hydrazinocarbonylmethyl-4-anisidine. The filtrate was concentrated and chromatographed on silica gel eluting with ethyl acetate:hexane (1:1) to give 0.7 g of 5-methoxy-2-oxindole as a yellow solid. The 1. 1 g of 2-hydrazinocarbonylmethyl-4-anisidine was refluxed for 1 hour in 20 mL of 1 N sodium hydroxide. The mixture was cooled, acidified to pH 2 with concentrated hydrochloric acid and extracted 3 times with 25 mL of ethyl acetate each time. The organic extracts were combined, washed with brine, dried over anhydrous sodium sulfate and concentrated to give 0.8 g of 5-methoxy-2-oxindole as a yellow solid. The combined yield was 1.5 g or 33%.
7-Azaoxindole
3,3-Dibromo-7-azaoxindole (2.9 g) was dissolved in a mixture of 20 mL of acetic acid and 30 mL of acetonitrile. To the solution was added 6.5 g of zinc dust. The mixture was stirred for 2 hrs at room temperature. The solid was filtered from the mixture and the solvent evaporated. The residue was slurried with ethyl acetate. The ethyl acetate solution containing insoluble solid was passed through a short column of silica gel. The collected ethyl acetate solution was evaporated and the residue dried under vacuum to give 1.8 g (yield 91%) of 7-azaoxindole acetic acid salt.
5-Dimethylaminosulfonyl-2-oxindole
A suspension of 2.3 g 5-chlorosulfonyl-2-oxindole in 10 mL 2 M dimethylamine in methanol was stirred at room temperature for 4 hours at which time a white solid formed. The precipitate was collected by vacuum filtration, washed with 5 mL 1 N sodium hydroxide and 5 mL of 1 N hydrochloric acid and dried under vacuum at 40xc2x0 C. overnight to give 1.9 g (79% yield) of 5-dimethylaminosulfonyl-2-oxindole.
6-Phenyl-2-oxindole
Dimethyl malonate (10 mL) in 25 mL of dimethylsulfoxide was added dropwise to 3.5 g sodium hydride suspended in 25 mL dimethylsulfoxide and the mixture heated at 100xc2x0 C. for 10 minutes. The mixture was cooled to room temperature and 4.7 g of 4-fluoro-3-nitrobiphenyl in 25 mL dimethylsulfoxide was added. The mixture was heated at 100xc2x0 C. for 2 hours, cooled and quenched with 300 mL of saturated ammonium chloride solution. The mixture was extracted three times with ethyl acetate and the combined organic layers washed with water and brine and evaporated to give, as a yellow oil, crude dimethyl-3-nitrobiphenyl-4-malonate.
Crude dimethyl-3-nitrobiphenyl-4-malonate was refluxed in 30 mL of 6 N hydrochloric acid for 24 hours. The precipitate was collected by filtration, washed with water and dried to give 4.5 g of 3-nitrobiphenyl-4-acetic acid as a cream colored solid.
Iron powder (2.6 g) was added all at once to 4.5 g of 3-nitrobiphenyl-4-acetic acid in 40 mL of acetic acid. The mixture was refluxed for 2 hours, concentrated to dryness and taken up in ethyl acetate. The solids were removed by filtration and the filtrate washed twice with 1 N hydrochloric acid and brine and dried over anhydrous sodium sulfate. The filtrate was concentrated to give 3.4 g (93% yield) of 6-phenyl-2-oxindole as a light brown solid.
6-(2-Methoxyphenyl)-2-oxindole
Tetrakis(triphenylphosphine)palladium (I g) was added to a mixture of 5 g 2-methoxyphenylboronic acid, 6.6 g 5-bromo-2-fluoronitrobenzene and 30 mL of 2 M sodium carbonate solution in 50 mL of toluene and 50 mL of ethanol. The mixture was refluxed for 2 hours, concentrated, and the residue extracted twice with ethyl acetate. The ethyl acetate layer was washed with water and brine, then dried, and concentrated to give a dark green oil which solidified on standing, crude 4-fluoro-2xe2x80x2-methoxy-3-nitrobiphenyl.
Dimethyl malonate (14 mL) was added dropwise to 2.9 g of sodium hydride suspended in 50 mL of dimethylsulfoxide. The mixture was heated at 100xc2x0 C. for 15 minutes and cooled to room temperature. Crude 4-fluoro-2xe2x80x2-methoxy-3-nitrobiphenyl in 60 mL of dimethylsulfoxide was added and the mixture was heated at 100xc2x0 C. for 2 hours. The reaction mixture was cooled and quenched with 300 mL of saturated sodium chloride solution and extracted twice with ethyl acetate. The extracts were combined, washed with saturated ammonium chloride, water and brine, dried over anhydrous sodium sulfate and concentrated to give crude dimethyl 2xe2x80x2-methoxy-3-nitrobiphenyl-4-malonate as a yellow oil.
Crude dimethyl 2xe2x80x2-methoxy-3-nitrobiphenyl-4-malonate was heated at 100xc2x0 C. in 50 mL of 6 N hydrochloric acid for 24 hours and cooled. The precipitate was collected by filtration, washed with water and hexane, and dried to give 9.8 of 2xe2x80x2-methoxy-2-nitrobiphenyl-4acetic acid as a light tan solid.
Iron powder (5 g) was added in one portion to 9.8 g of 2xe2x80x2-methoxy-3-nitrobiphenyl-4-acetic acid in 50 mL of glacial acetic acid was heated to 100xc2x0 C. for 3 hours. The reaction mixture was concentrated to dryness, sonicated in ethyl acetate and filtered to remove the insolubles. The filtrate was washed twice with 1 N hydrochloric acid, water and then brine, dried over anhydrous sodium sulfate and concentrated. The residue was chromatographed on silica gel in ethyl acetate:hexane (1:2) to give 5.4 g of 6-(2-methoxyphenyl)-2-oxindole as a rose colored solid.
6-(3-Methoxyphenyl)-2-oxindole
Tetrakis(triphenylphosphine)palladium (0.8 g) was added to a mixture of 5 g 3-methoxyphenylboronic acid, 5 g 5-bromo-2-fluoronitrobenzene and 11 mL of 2 M sodium carbonate solution in 100 mL of toluene. The mixture was refluxed for 2 hours, diluted with water and extracted with ethyl acetate. The ethyl acetate was washed with saturated sodium bicarbonate and brine and then dried and concentrated to give an oily solid. The solid was chromatographed on silica gel (ethyl acetate:hexane (1:6)) to give 4.3 g (77% yield) of 4-fluoro-3xe2x80x2-methoxy-3-nitrobiphenyl.
Dimethyl malonate (9.7 mL) was added dropwise to 2.0 g sodium hydride suspended in 50 mL dimethylsulfoxide. The mixture was heated to 100xc2x0 C. for 35 minutes and cooled to room temperature. 4-Fluoro-2xe2x80x2-methoxy-3-nitrobiphenyl (4.2 g) in 50 mL dimethylsulfoxide was added and the mixture was heated at 100xc2x0 C. for 1 hour. The reaction mixture was cooled and quenched with 300 mL of saturated ammonium chloride solution and extracted twice with ethyl acetate. The extracts were combined, washed with brine, dried over anhydrous sodium sulfate and concentrated to give crude dimethyl 3xe2x80x2-methoxy-3-nitrobiphenyl-4-malonate as a pale yellow solid.
Crude dimethyl 3xe2x80x2-methoxy-3-nitrobiphenyl-4-malonate was heated at 110xc2x0 C. in 45 mL 6 N hydrochloric acid for 4 days and then cooled. The precipitate was collected by filtration, washed with water and hexane, and dried to give 5.3 g of 3xe2x80x2-methoxy-2-nitrobiphenyl-4-acetic acid as a light tan solid.
3xe2x80x2-Methoxy-3-nitrobiphenyl-4-acetic acid (5.2 g) was dissolved in methanol and hydrogenated over 0.8 g of 10% palladium on carbon for 3 hours at room temperature. The catalyst was removed by filtration, washed with methanol and the filtrates combined and concentrated to give a brown solid. The solid was chromatographed on silica gel in ethyl acetate:hexane:acetic acid (33:66:1) to give 3.0 g of 6-(3-methoxypheny)-2-oxindole as a pink solid.
6-(4-Methoxyphenyl)-2-oxindole
Tetrakis(triphenylphosphine)palladium (I g) was added to a mixture of 5 g of 4methoxyphenylboronic acid, 6.6 g of 5-bromo-2-fluoronitrobenzene and 30 mL of 2 M sodium carbonate solution in 50 mL of toluene and 50 mL of ethanol. The mixture was refluxed for 2 hours, concentrated, and the residue extracted twice with ethyl acetate. The ethyl acetate layer was washed with water and brine, dried, and concentrated to give a brown oily solid. The solid was chromatographed on silica gel (5% ethyl acetate in hexane) to give crude 4-fluoro-4xe2x80x2-methoxy-3-nitrobiphenyl as a pale yellow solid.
Dimethyl malonate (10 mL) was added dropwise to 2.0 g of sodium hydride suspended in 60 mL of dimethylsulfoxide. The mixture was heated to 100xc2x0 C. for 10 minutes and cooled to room temperature. Crude 4-fluoro-2xe2x80x2-methoxy-3-nitrobiphenyl (5.2 g) in 50 mL dimethylsulfoxide was added and the mixture was heated at 100xc2x0 C. for 2 hours. The reaction mixture was cooled and quenched with 300 mL of saturated sodium chloride solution and extracted three times with ethyl acetate. The extracts were combined, washed with saturated ammonium chloride, water and brine, dried over anhydrous sodium sulfate and concentrated to give crude dimethyl 4xe2x80x2-methoxy-3-nitrobiphenyl-4malonate as a yellow oil.
Crude dimethyl 4xe2x80x2-methoxy-3-nitro-biphenyl-4-malonate was heated at 100xc2x0 C. in 60 mL of 6 N hydrochloric acid for 15 hours and cooled. The precipitate was collected by filtration, washed with water and hexane, and dried to give 7.2 g of crude 4xe2x80x2-methoxy-3nitrobiphenyl-4-acetic acid as a light tan solid.
Iron powder (3.6 g) was added in one portion to 7.2 g of 4xe2x80x2-methoxy-3-nitrobiphenyl-4-acetic acid in 50 mL of glacial acetic acid and heated at 100xc2x0 C. overnight. The reaction mixture was concentrated to dryness, sonicated in ethyl acetate and filtered to remove the insolubles. The filtrate was washed twice with 1 N hydrochloric acid and brine, dried over anhydrous sodium sulfate and concentrated to give 2.7 g of 6-(4-methoxyphenyl)-2-oxindole as a rose colored solid.
6-(3-Ethoxyphenyl)-2-oxindole
Tetrakis(triphenylphosphine)palladium (0.8 g) was added to a mixture of 4.2 g of 3-ethoxyphenylboronic acid, 5.0 g of 5-bromo-2-fluoronitrobenzene and 22 mL of 2 M sodium carbonate solution in 50 mL of toluene and 50 mL of ethanol. The mixture was refluxed for 2 hours, concentrated, water was added and the mixture was extracted twice with ethyl acetate. The ethyl acetate layer was washed with water and brine, then dried, and concentrated. The residue was chromatographed on silica gel (5% ethyl acetate in hexane) to give 5.3 g (90% yield) of crude 4-fluoro-3xe2x80x2-ethoxy-3-nitrobiphenyl as a yellow oil.
Dimethyl malonate (11.4 mL) was added dropwise to 4.0 g sodium hydride suspended in 20 mL dimethylsulfoxide. The mixture was heated to 100xc2x0 C. for 10 minutes and then cooled to room temperature. Crude 4-fluoro-3xe2x80x2-ethoxy-3-nitrobiphenyl (5.3 g) in 25 mL of dimethylsulfoxide was added and the mixture was heated at 100xc2x0 C. for 2 hours. The reaction mixture was cooled and quenched with 300 mL of saturated ammonium chloride solution and extracted three times with ethyl acetate. The extracts were combined, washed with water and brine and then dried over anhydrous sodium sulfate and concentrated to give crude dimethyl 3xe2x80x2-ethoxy-3-nitrobiphenyl-4-malonate as a yellow oil.
Crude dimethyl 3xe2x80x2-ethoxy-3-nitrobiphenyl-4-malonate was heated at 100xc2x0 C. in 60 mL of 6 N hydrochloric acid for 4 days and then cooled. The precipitate was collected by filtration, washed with water and hexane, and dried to give 4.7 g of crude 3xe2x80x2-ethoxy-3-nitrobiphenyl-4-acetic acid as a light tan solid.
Iron powder (2.4 g) was added in one portion to 4.6 g of 3xe2x80x2-ethoxy-3-nitrobiphenyl-4-acetic acid in 40 mL of glacial acetic acid and refluxed for 2 hours. The reaction mixture was concentrated to dryness, treated repeatedly with ethyl acetate and filtered to remove the insolubles. The filtrate was washed twice with 1 N hydrochloric acid and brine and then dried over anhydrous sodium sulfate and concentrated to give 3.5 g (91% yield) of 6-(3-ethoxyphenyl)-2-oxindole as a light brown solid.
6-Bromo-2-oxindole
Dimethyl malonate (13 mL) was added dropwise to 2.7 g sodium hydride suspended in 20 mL dimethylsulfoxide. The mixture was heated to 100xc2x0 C. for 10 minutes and then cooled to room temperature. 5-Bromo-2-fluoronitrobenzene (5.0 g) in 25 mL of dimethylsulfoxide was added and the mixture was heated at 100xc2x0 C. for 2 hours. The reaction mixture was cooled and quenched with 300 mL of saturated ammonium chloride solution and extracted three times with ethyl acetate. The extracts were combined, washed with saturated ammonium chloride, water and brine, dried over anhydrous sodium sulfate and concentrated to give crude dimethyl 4-bromo-2-nitrophenylmalonate as a pale yellow oil.
Crude dimethyl 4-bromo-2-nitrophenylmalonate was heated at 110xc2x0 C. in 40 mL of 6 N hydrochloric acid for 24 hours and then cooled. The precipitate was collected by filtration, washed with water and dried to give 5.3 g (89% yield) of 4-bromo-2-nitrophenylacetic acid as an off white solid.
4-Bromo-2-nitrophenylacetic acid (0.26 g), 0.26 g zinc powder and 3 mL 50% sulfuric acid in 5 mL of ethanol were heated at 100xc2x0 C. overnight. The reaction mixture was filtered, diluted with a little acetic acid, concentrated to remove ethanol, diluted with water and extracted twice with ethyl acetate. The combined extracts were washed with brine, dried over anhydrous sodium sulfate and concentrated to give 0.19 g (90% yield) of 6-bromo-2-oxindole as a yellow solid.
5-Acetyl-2-oxindole
2-Oxindole (3 g) was suspended in 1,2-dichloroethane and 3.2 mL acetyl chloride were slowly added. The resulting suspension was heated to 50xc2x0 C. for 5 hours, cooled, and poured into water. The resulting precipitate was collected by vacuum filtration, washed copiously with water and dried under vacuum to give 2.9 g (73% yield) of the title compound as a brown solid.
5-Butanoyl-2-oxindole
To 15 g aluminum chloride suspended in 30 mL 1,2-dichloroethane in an ice bath was added 7.5 g of 2-oxindole and then 12 g of butanoyl chloride. The resulting suspension was heated to 50xc2x0 C. overnight. The mixture was poured into ice water and extracted 3 times with ethyl acetate. The combined ethyl acetate layers were washed with brine, dried over sodium sulfate, and concentrated to dryness to give a brown solid. The solid was chromatographed on silica gel (50% ethyl acetate in hexane) to give 3 g (25%) of the title compound as a yellow solid.
5-Cyanoethyl-2-oxindole
Potassium cyanide (2.0 g) was added to 15 mL of dimethylsulfoxide and heated to 90xc2x0 C. 5-Chloroethyl-2-oxindole (3.0 g) dissolved in 5 mL dimethyl sulfoxide was added slowly with stirring, and the reaction heated to 150xc2x0 C. for 2 hours. The mixture was cooled, poured into ice water and the precipitate collected by vacuum filtration, washed with water, dried and then chromatographed on silica gel (5% methanol in chloroform) to give 1.2 g (42% yield) of the title compound.
6-Morpholin-4-yl)-2-oxindole
6-Amino-2-oxindole (2.2 g), 4.0 g 2, 2xe2x80x2-dibromoethyl ether and 7.9 g sodium carbonate were refluxed in 20 ml ethanol overnight, concentrated and diluted with 50 ml of water. The mixture was extracted three times with 50 ml of ethyl acetate and the organic extracts combined, washed with 20 ml of brine, dried over anhydrous sodium sulfate and concentrated to dryness. The solid was chromatographed on a column of silica gel (ethyl acetate:hexane (1:1) containing 0.7% acetic acid) to give 1.2 g (37% yield) of the title compound as a beige solid.
6-(3-Trifluoroacetylphenyl)-2-oxindole
3-Aminophenylboronic acid (3.9 g), 5 g 5-bromo-2-fluoronitrobenzene, 0.8 g tetrakis(triphenylphosphine)palladium and 23 mL of 2 M sodium bicarbonate solution in 50 mL of toluene were refluxed under nitrogen for 2.5 hours. The reaction mixture was poured into 200 mL of ice water and the mixture extracted three times with 50 mL of ethyl acetate. The combined organic layers were washed with 50 mL of water and 20 mL of brine, dried over anhydrous sodium sulfate and concentrated to give 9.7 g (92% yield) of 2-fluoro-5-(3-aminophenyl)nitrobenzene as a dark brown oil.
Trifluoroacetic anhydride (5.4 mL) was slowly added to a stirred solution of 9.7 g 2-fluoro-5-(3-aminophenyl)nitrobenzene and 5.3 mL of triethylamine in 50 mL of dichloromethane at 0xc2x0 C. and the mixture was stirred for an additional 20 minutes. The mixture was concentrated and the residue chromatographed on a column of silica gel (10% ethyl acetate in hexane) to give 8.6 g (65% yield) of 2-fluoro-5-(3-trifluoroacetamidophenyl)nitrobenzene as a pale orange oil which solidified on standing.
Dimethyl malonate (9.6 mL) was added dropwise to a stirred suspension of 3.2 g of 60% sodium hydride in mineral oil in 40 mL anhydrous dimethylsulfoxide under nitrogen. The mixture was stirred for 10 minutes and 2-fluoro-5-(3-trifluoroacetamidophenyl)nitrobenzene in 20 mL dimethylsulfoxide was added. The resulting dark red mixture was heated to 100xc2x0 C. for 2 hours. The reaction was quenched by pouring into 100 mL of saturated ammonium chloride solution and extracted twice with 50 mL of ethyl acetate. The organic phase was washed with 50 mL each of saturated ammonium chloride solution, water, and brine, dried over anhydrous sodium sulfate and concentrated to a yellow oil. The oil was chromatographed on a column of silica gel (ethyl acetate:hexane (1:4)) to give 4.4 g (50% yield) of dimethyl 2-[2-nitro-4-(3-trifluoroacetamidophenyl)phenyl]-malonate as a pale yellow solid.
Dimethyl 2-[2-nitro-4-(3-trifluoroacetamidophenyl)phenyl]malonate (4.4 g) was refluxed overnight in 50 mL 6 N hydrochloric acid. The reaction mixture was cooled to room temperature and the solids were collected by vacuum filtration, washed with water, and dried under vacuum to give 2.7 g (73% yield) of 2-[2-nitro-4-(3-trifluoroacetamidophenyl)phenyl] acetic acid.
2-[2-Nitro-4-(3-trifluoroacetamidophenyl)phenyl]acetic acid (100 mg) and 50 mg iron powder in 3 mL acetic acid was heated at 100xc2x0 C. for 2 hours. The reaction mixture was concentrated and the residue sonicated in 5 mL ethyl acetate. The insoluble solids were removed by vacuum filtration and the filtrate washed with 1 N hydrochloric acid, water and brine, dried over anhydrous sodium sulfate and concentrated to give 10 mg (14% yield) of the title compound as a rose-colored solid.
B. Aldehydes
5-Formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid
t-Butyl-3-oxobutyrate (158 g, 1 mol) was dissolved in 200 mL of acetic acid in a 500 mL 3-neck round bottom flask equipped with a thermometer, addition funnel and mechanical stirring. The mixture was cooled in an ice bath to about 10xc2x0 C. Sodium nitrite (69 g, 1 mol) was added over 75 minutes keeping the temperature under 15xc2x0 C. The cold bath was removed and the mixture stirred for 30 minutes and then allowed to stand for 3.5 hours to give t-butyl-2-hydroximino-3-oxobutyrate.
Ethyl-3-oxobutyrate (130 g, 1 mol) was dissolved in 400 mL of acetic acid in a 2 L 3-neck round bottom flask equipped with a thermometer, an addition funnel, mechanical stirring and placed in an oil bath. Zinc dust (50 g, 0.76 mol) was added and the mixture heated to 60xc2x0 C. with stirring. The t-butyl-2-hydroximino-3-oxobutyrate solution prepared above was slowly added, the temperature of the reaction mixture being maintained at about 65xc2x0 C. More zinc dust was then added (4xc3x9750 g, 3.06 mol) with the last portion added after all the t-butyl ester had been added. At the end of the additions the temperature was 64xc2x0 C. The temperature was increased to 70-75xc2x0 C., stirred for one hour and then poured into 5 L of water. The gray floating precipitate was collected by vacuum filtration and washed with 2 L of water to give 354 g of wet crude product. The crude product was dissolved in 1 L of hot methanol and filtered hot to remove zinc. The filtrate was cooled upon which a precipate formed. The precipitate that was collected by vacuum filtration and dried to give 118 g of product. The filtrate was put in the refrigerator overnight uon which additional product precipated. A total of 173.2 g of 3,5-dimethyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester was obtained.
3,5-Dimethyl-1H-pyrrole-2,4-dicarboxylic acid 2-tert-butyl ester 4-ethyl ester (80.1 g, 0.3 mol) and 400 mL trifluoroacetic acid were stirred for 5 minutes in a 2 L 3-neck round bottom flask equipped with mechanical stirring and warmed to 40xc2x0 C. in an oil bath. The mixture was then cooled to xe2x88x925xc2x0 C. and triethyl orthoformate (67.0 g, 0.45 mol) was added all at once. The temperature increased to 15xc2x0 C. The mixture was stirred for about 1 minute, removed from the cold bath and then stirred for 1 hour. The trifluoroacetic acid was removed by rotary evaporation and the residue put in the refrigerator where it solidified. The solid was dissolved by warming and poured into 500 g of ice. The mixture was extracted with 800 mL of dichloromethane to give a red solution and a brown precipitate, both of which were saved. The precipitate was isolated and washed with 150 mL of saturated sodium bicarbonate solution. The dichoromethane phase was also washed with 150 mL of sodium bicarbonate. The dichloromethane solution was then washed 3 more times with 100 mL of water. The dichloromethane solution was evaporated to dryness. The dark residue which remained was recrystallized twice from ethyl acetate containing Darco carbon black to give golden yellow needles. The brown precipitate was recrystallized from 350 mL ethyl acetate likewise containing Darco to give a yellow-red solid. All the recrystallized solids were combined and recrystallized from 500 mL of ethanol to give 37.4 g (63.9%) of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester as yellow needles (mp 165.6-166.3xc2x0 C., lit. 163-164xc2x0 C.). The residues obtained after evaporationg of the ethyl acetate and ethanol mother liquors were combined and recrystallized from 500 mL of ethanol to give a second crop (10.1 g) or product as dirty yellow needles.
5-Formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid ethyl ester (2 g, 10 mmol) was added to a solution of potassium hydroxide (3 g, 53 mmol) dissolved in methanol (3 mL) and water (10 mL). The mixture was refluxed for 3 hours, cooled to room temperature and acidified with 6 N hydrochloric acid to pH 3. The solid which formed was collected by filtration, washed with water and dried in a vacuum oven overnight to give 1.6 g (93%) of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid.
1H NMR (300 MHz, DMSO-d6)xcex4: 12.09 (s, br, 2 H, NH and COOH), 9.59 (s, 1 H, CHO), 2.44 (s, 3 H, CH3), 2.40 (s, 3 H, CH3).
5-Formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (2-dimethylaminoethyl) amide
To a mixture of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (1.67 g, 10 mmol) in dimethylforamide (10 mL) was added benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate (BOP reagent, 6 g, 13.5 mmol) followed by 3 mL diisopropylethylamine. After stirring for 5 minutes, 1 mL of N,N-dimethylethylendiamine was added and the mixture was stirred at room temperature for 24 hours. To the reaction mixture was added 25 mL of 1 N sodium hydroxide and 25 mL of brine. After stirring for 30 minutes, the reaction mixture was poured into water (100 mL) and extracted (3xc3x97200 mL) with 10% of methanol in dichloromethane. The organic layers were combined, dried over anhydrous sodium sulfate and evaporated using a rotary evaporator. The residue which remained was purified by chromatography (silica gel column, 5%-10% methanol in dichloromethane) to give 1 g (42%) of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (2-dimethylamino-ethyl)-amide.
1H NMR (360 MHz, DMSO-d6) xcex4: 11.77 (s, 1 H, NH), 9.53 (s, 1 H, CHO), 7.34 (t, J=5.6 Hz, 1 H, CONH), 3.27 (m, 2 H, CONCH2CH2), 2.37 (t, J=6.8 Hz, 2 H, CONCH2CH2), 2.35 (s, 3 H, CH3), 2.3 (s, 3 H, CH3), 2.17 (s, 6 H, 2xc3x97CH3).
MS m/z 238.3 [M+1]+.
3,5-dimethyl-4-(4-methyl-piperazine-1-carbonyl)-1H-pyrrole-2-carboxaldehyde
To a mixture of 5-formyl-2,4-dimethyl-1H-pyrrole-3-carboxylic acid (1.67 g, 10 mmol) in dimethylformamide (10 mL) was added benzotriazol-1-yloxytris(dimethylamino)-phosphonium hexafluorophosphate (BOP reagent, 6 g, 13.5 mmol) followed by 3 mL of diisopropylethylamine. After stirring for 5 minutes, 2 mL of 1-methylpiperazine was added and the mixture was stirred at room temperature for 24 hours. To the reaction was then added 25 mL of 1 N sodium hydroxide and 25 mL of brine. After stirring for 30 minutes, the reaction mixture was poured into water (100 mL) and extracted (3xc3x97200 mL) with 10% of methanol in dichloromethane. The organic layers were combined, dried over anhydrous sodium sulfate and evaporated on a rotary evaporator. The residue which remained was purified by chromatography(silica gel column, 5%-10% of methanol in dichloromethane) to give 1 g (40%) of 3,5-dimethyl-4-(4-methyl-piperazine-1-carbonyl)-1H-pyrrole-2-carboxaldehyde.
1H NMR (360 MHz, DMSO-d6)xcex4: 11.82 (s, 1 H, NH), 9.50 (s, 1 H, CHO), 3.14 (br m, 4 H, 2xc3x97CH2), 2.29 (br m, 4 H, 2xc3x97CH2), 2.19 (s, 3 H, CH3), 2.17 (s, 3 H, CH3), 2.14 (s, 3 H, CH3).
MS EI 249 [M]+.